Backhaul Link Connection Information

ABSTRACT

A wireless device communicates with a first network node via a second network node. The wireless device transmits a radio link failure report to a third network node. The radio link failure report indicates a backhaul link failure between the first network node and the second network node.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No. PCT/US2019/050226, filed Sep. 9, 2019, which claims the benefit of U.S. Provisional Application No. 62/728,782, filed Sep. 8, 2018, each of which is hereby incorporated by reference in its entirety.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Examples of several of the various embodiments of the present disclosure are described herein with reference to the drawings.

FIG. 1 is a diagram of an example RAN architecture as per an aspect of an embodiment of the present disclosure.

FIG. 2A is a diagram of an example user plane protocol stack as per an aspect of an embodiment of the present disclosure.

FIG. 2B is a diagram of an example control plane protocol stack as per an aspect of an embodiment of the present disclosure.

FIG. 3 is a diagram of an example wireless device and two base stations as per an aspect of an embodiment of the present disclosure.

FIG. 4A, FIG. 4B, FIG. 4C and FIG. 4D are example diagrams for uplink and downlink signal transmission as per an aspect of an embodiment of the present disclosure.

FIG. 5A is a diagram of an example uplink channel mapping and example uplink physical signals as per an aspect of an embodiment of the present disclosure.

FIG. 5B is a diagram of an example downlink channel mapping and example downlink physical signals as per an aspect of an embodiment of the present disclosure.

FIG. 6 is a diagram depicting an example frame structure as per an aspect of an embodiment of the present disclosure.

FIG. 7A and FIG. 7B are diagrams depicting example sets of OFDM subcarriers as per an aspect of an embodiment of the present disclosure.

FIG. 8 is a diagram depicting example OFDM radio resources as per an aspect of an embodiment of the present disclosure.

FIG. 9A is a diagram depicting an example CSI-RS and/or SS block transmission in a multi-beam system.

FIG. 9B is a diagram depicting an example downlink beam management procedure as per an aspect of an embodiment of the present disclosure.

FIG. 10 is an example diagram of configured BWPs as per an aspect of an embodiment of the present disclosure.

FIG. 11A, and FIG. 11B are diagrams of an example multi connectivity as per an aspect of an embodiment of the present disclosure.

FIG. 12 is a diagram of an example random access procedure as per an aspect of an embodiment of the present disclosure.

FIG. 13 is a structure of example MAC entities as per an aspect of an embodiment of the present disclosure.

FIG. 14 is a diagram of an example RAN architecture as per an aspect of an embodiment of the present disclosure.

FIG. 15 is a diagram of example RRC states as per an aspect of an embodiment of the present disclosure.

FIG. 16 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 17 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 18 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 19 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 20 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 21 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 22 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 23 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 24 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 25 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 26 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 27 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 28 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 29 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 30 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 31 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 32 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 33 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 34 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 35 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 36 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 37 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 38 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 39 is a diagram of an aspect of an example embodiment of the present disclosure.

FIG. 40 is a flow diagram of an aspect of an example embodiment of the present disclosure.

FIG. 41 is a flow diagram of an aspect of an example embodiment of the present disclosure.

FIG. 42 is a flow diagram of an aspect of an example embodiment of the present disclosure.

FIG. 43 is a flow diagram of an aspect of an example embodiment of the present disclosure.

FIG. 44 is a flow diagram of an aspect of an example embodiment of the present disclosure.

FIG. 45 is a flow diagram of an aspect of an example embodiment of the present disclosure.

FIG. 46 is a flow diagram of an aspect of an example embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Example embodiments of the present disclosure enable operation of wireless systems. Embodiments of the technology disclosed herein may be employed in the technical field of multicarrier communication systems. More particularly, the embodiments of the technology disclosed herein may relate to radio access technologies in multicarrier communication systems.

The following Acronyms are used throughout the present disclosure:

-   -   3GPP 3rd Generation Partnership Project     -   5GC 5G Core Network     -   ACK Acknowledgement     -   AMF Access and Mobility Management Function     -   ARQ Automatic Repeat Request     -   AS Access Stratum     -   ASIC Application-Specific Integrated Circuit     -   BA Bandwidth Adaptation     -   BCCH Broadcast Control Channel     -   BCH Broadcast Channel     -   BPSK Binary Phase Shift Keying     -   BWP Bandwidth Part     -   CA Carrier Aggregation     -   CC Component Carrier     -   CCCH Common Control CHannel     -   CDMA Code Division Multiple Access     -   CN Core Network     -   CP Cyclic Prefix     -   CP-OFDM Cyclic Prefix—Orthogonal Frequency Division Multiplex     -   C-RNTI Cell-Radio Network Temporary Identifier     -   CS Configured Scheduling     -   CSI Channel State Information     -   CSI-RS Channel State Information-Reference Signal     -   CQI Channel Quality Indicator     -   CSS Common Search Space     -   CU Central Unit     -   DC Dual Connectivity     -   DCCH Dedicated Control CHannel     -   DCI Downlink Control Information     -   DL Downlink     -   DL-SCH Downlink Shared CHannel     -   DM-RS DeModulation Reference Signal     -   DRB Data Radio Bearer     -   DRX Discontinuous Reception     -   DTCH Dedicated Traffic CHannel     -   DU Distributed Unit     -   EPC Evolved Packet Core     -   E-UTRA Evolved UMTS Terrestrial Radio Access     -   E-UTRAN Evolved-Universal Terrestrial Radio Access Network     -   FDD Frequency Division Duplex     -   FPGA Field Programmable Gate Arrays     -   F1-C F1-Control plane     -   F1-U F1-User plane     -   gNB next generation Node B     -   HARQ Hybrid Automatic Repeat reQuest     -   HDL Hardware Description Languages     -   IAB Integrated Access and Backhaul     -   IE Information Element     -   IP Internet Protocol     -   LCID Logical Channel IDentifier     -   LTE Long Term Evolution     -   MAC Media Access Control     -   MCG Master Cell Group     -   MCS Modulation and Coding Scheme     -   MeNB Master evolved Node B     -   MIB Master Information Block     -   MME Mobility Management Entity     -   MN Master Node     -   NACK Negative Acknowledgement     -   NAS Non-Access Stratum     -   NG CP Next Generation Control Plane     -   NGC Next Generation Core     -   NG-C NG-Control plane     -   ng-eNB next generation evolved Node B     -   NG-U NG-User plane     -   NR New Radio     -   NR MAC New Radio MAC     -   NR PDCP New Radio PDCP     -   NR PHY New Radio PHYsical     -   NR RLC New Radio RLC     -   NR RRC New Radio RRC     -   NSSAI Network Slice Selection Assistance Information     -   O&M Operation and Maintenance     -   OFDM Orthogonal Frequency Division Multiplexing     -   PBCH Physical Broadcast CHannel     -   PCC Primary Component Carrier     -   PCCH Paging Control CHannel     -   PCell Primary Cell     -   PCH Paging CHannel     -   PDCCH Physical Downlink Control CHannel     -   PDCP Packet Data Convergence Protocol     -   PDSCH Physical Downlink Shared CHannel     -   PDU Protocol Data Unit     -   PHICH Physical HARQ Indicator CHannel     -   PHY PHYsical     -   PLMN Public Land Mobile Network     -   PMI Precoding Matrix Indicator     -   PRACH Physical Random Access CHannel     -   PRB Physical Resource Block     -   PSCell Primary Secondary Cell     -   PSS Primary Synchronization Signal     -   pTAG primary Timing Advance Group     -   PT-RS Phase Tracking Reference Signal     -   PUCCH Physical Uplink Control CHannel     -   PUSCH Physical Uplink Shared CHannel     -   QAM Quadrature Amplitude Modulation     -   QFI Quality of Service Indicator     -   QoS Quality of Service     -   QPSK Quadrature Phase Shift Keying     -   RA Random Access     -   RACH Random Access CHannel     -   RAN Radio Access Network     -   RAT Radio Access Technology     -   RA-RNTI Random Access-Radio Network Temporary Identifier     -   RB Resource Blocks     -   RBG Resource Block Groups     -   RI Rank Indicator     -   RLC Radio Link Control     -   RRC Radio Resource Control     -   RS Reference Signal     -   RSRP Reference Signal Received Power     -   SCC Secondary Component Carrier     -   SCell Secondary Cell     -   SCG Secondary Cell Group     -   SC-FDMA Single Carrier-Frequency Division Multiple Access     -   SDAP Service Data Adaptation Protocol     -   SDU Service Data Unit     -   SeNB Secondary evolved Node B     -   SFN System Frame Number     -   S-GW Serving GateWay     -   SI System Information     -   SIB System Information Block     -   SMF Session Management Function     -   SN Secondary Node     -   SpCell Special Cell     -   SRB Signaling Radio Bearer     -   SRS Sounding Reference Signal     -   SS Synchronization Signal     -   SSS Secondary Synchronization Signal     -   sTAG secondary Timing Advance Group     -   TA Timing Advance     -   TAG Timing Advance Group     -   TAI Tracking Area Identifier     -   TAT Time Alignment Timer     -   TB Transport Block     -   TC-RNTI Temporary Cell-Radio Network Temporary Identifier     -   TDD Time Division Duplex     -   TDMA Time Division Multiple Access     -   TTI Transmission Time Interval     -   UCI Uplink Control Information     -   UE User Equipment     -   UL Uplink     -   UL-SCH Uplink Shared CHannel     -   UPF User Plane Function     -   UPGW User Plane Gateway     -   VHDL VHSIC Hardware Description Language     -   Xn-C Xn-Control plane     -   Xn-U Xn-User plane

Example embodiments of the disclosure may be implemented using various physical layer modulation and transmission mechanisms. Example transmission mechanisms may include, but are not limited to: Code Division Multiple Access (CDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Time Division Multiple Access (TDMA), Wavelet technologies, and/or the like. Hybrid transmission mechanisms such as TDMA/CDMA, and OFDM/CDMA may also be employed. Various modulation schemes may be applied for signal transmission in the physical layer. Examples of modulation schemes include, but are not limited to: phase, amplitude, code, a combination of these, and/or the like. An example radio transmission method may implement Quadrature Amplitude Modulation (QAM) using Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), 16-QAM, 64-QAM, 256-QAM, and/or the like. Physical radio transmission may be enhanced by dynamically or semi-dynamically changing the modulation and coding scheme depending on transmission requirements and radio conditions.

FIG. 1 is an example Radio Access Network (RAN) architecture as per an aspect of an embodiment of the present disclosure. As illustrated in this example, a RAN node may be a next generation Node B (gNB) (e.g. 120A, 120B) providing New Radio (NR) user plane and control plane protocol terminations towards a first wireless device (e.g. 110A). In an example, a RAN node may be a next generation evolved Node B (ng-eNB) (e.g. 124A, 124B), providing Evolved UMTS Terrestrial Radio Access (E-UTRA) user plane and control plane protocol terminations towards a second wireless device (e.g. 110B). The first wireless device may communicate with a gNB over a Uu interface. The second wireless device may communicate with a ng-eNB over a Uu interface. In this disclosure, wireless device 110A and 110B are structurally similar to wireless device 110. Base stations 120A and/or 120B may be structurally similarly to base station 120. Base station 120 may comprise at least one of a gNB (e.g. 122A and/or 122B), ng-eNB (e.g. 124A and/or 124B), and or the like.

A gNB or an ng-eNB may host functions such as: radio resource management and scheduling, IP header compression, encryption and integrity protection of data, selection of Access and Mobility Management Function (AMF) at User Equipment (UE) attachment, routing of user plane and control plane data, connection setup and release, scheduling and transmission of paging messages (originated from the AMF), scheduling and transmission of system broadcast information (originated from the AMF or Operation and Maintenance (O&M)), measurement and measurement reporting configuration, transport level packet marking in the uplink, session management, support of network slicing, Quality of Service (QoS) flow management and mapping to data radio bearers, support of UEs in RRC_INACTIVE state, distribution function for Non-Access Stratum (NAS) messages, RAN sharing, and dual connectivity or tight interworking between NR and E-UTRA.

In an example, one or more gNBs and/or one or more ng-eNBs may be interconnected with each other by means of Xn interface. A gNB or an ng-eNB may be connected by means of NG interfaces to 5G Core Network (5GC). In an example, 5GC may comprise one or more AMF/User Plan Function (UPF) functions (e.g. 130A or 130B). A gNB or an ng-eNB may be connected to a UPF by means of an NG-User plane (NG-U) interface. The NG-U interface may provide delivery (e.g. non-guaranteed delivery) of user plane Protocol Data Units (PDUs) between a RAN node and the UPF. A gNB or an ng-eNB may be connected to an AMF by means of an NG-Control plane (NG-C) interface. The NG-C interface may provide, for example, NG interface management, UE context management, UE mobility management, transport of NAS messages, paging, PDU session management, configuration transfer and/or warning message transmission, combinations thereof, and/or the like.

In an example, a UPF may host functions such as anchor point for intra-/inter-Radio Access Technology (RAT) mobility (when applicable), external PDU session point of interconnect to data network, packet routing and forwarding, packet inspection and user plane part of policy rule enforcement, traffic usage reporting, uplink classifier to support routing traffic flows to a data network, branching point to support multi-homed PDU session, QoS handling for user plane, e.g. packet filtering, gating, Uplink (UL)/Downlink (DL) rate enforcement, uplink traffic verification (e.g. Service Data Flow (SDF) to QoS flow mapping), downlink packet buffering and/or downlink data notification triggering.

In an example, an AMF may host functions such as NAS signaling termination, NAS signaling security, Access Stratum (AS) security control, inter Core Network (CN) node signaling for mobility between 3^(rd) Generation Partnership Project (3GPP) access networks, idle mode UE reachability (e.g., control and execution of paging retransmission), registration area management, support of intra-system and inter-system mobility, access authentication, access authorization including check of roaming rights, mobility management control (subscription and policies), support of network slicing and/or Session Management Function (SMF) selection.

FIG. 2A is an example user plane protocol stack, where Service Data Adaptation Protocol (SDAP) (e.g. 211 and 221), Packet Data Convergence Protocol (PDCP) (e.g. 212 and 222), Radio Link Control (RLC) (e.g. 213 and 223) and Media Access Control (MAC) (e.g. 214 and 224) sublayers and Physical (PHY) (e.g. 215 and 225) layer may be terminated in wireless device (e.g. 110) and gNB (e.g. 120) on the network side. In an example, a PHY layer provides transport services to higher layers (e.g. MAC, RRC, etc.). In an example, services and functions of a MAC sublayer may comprise mapping between logical channels and transport channels, multiplexing/demultiplexing of MAC Service Data Units (SDUs) belonging to one or different logical channels into/from Transport Blocks (TBs) delivered to/from the PHY layer, scheduling information reporting, error correction through Hybrid Automatic Repeat request (HARQ) (e.g. one HARQ entity per carrier in case of Carrier Aggregation (CA)), priority handling between UEs by means of dynamic scheduling, priority handling between logical channels of one UE by means of logical channel prioritization, and/or padding. A MAC entity may support one or multiple numerologies and/or transmission timings. In an example, mapping restrictions in a logical channel prioritization may control which numerology and/or transmission timing a logical channel may use. In an example, an RLC sublayer may supports transparent mode (TM), unacknowledged mode (UM) and acknowledged mode (AM) transmission modes. The RLC configuration may be per logical channel with no dependency on numerologies and/or Transmission Time Interval (TTI) durations. In an example, Automatic Repeat Request (ARQ) may operate on any of the numerologies and/or TTI durations the logical channel is configured with. In an example, services and functions of the PDCP layer for the user plane may comprise sequence numbering, header compression and decompression, transfer of user data, reordering and duplicate detection, PDCP PDU routing (e.g. in case of split bearers), retransmission of PDCP SDUs, ciphering, deciphering and integrity protection, PDCP SDU discard, PDCP re-establishment and data recovery for RLC AM, and/or duplication of PDCP PDUs. In an example, services and functions of SDAP may comprise mapping between a QoS flow and a data radio bearer. In an example, services and functions of SDAP may comprise mapping Quality of Service Indicator (QFI) in DL and UL packets. In an example, a protocol entity of SDAP may be configured for an individual PDU session.

FIG. 2B is an example control plane protocol stack where PDCP (e.g. 233 and 242), RLC (e.g. 234 and 243) and MAC (e.g. 235 and 244) sublayers and PHY (e.g. 236 and 245) layer may be terminated in wireless device (e.g. 110) and gNB (e.g. 120) on a network side and perform service and functions described above. In an example, RRC (e.g. 232 and 241) may be terminated in a wireless device and a gNB on a network side. In an example, services and functions of RRC may comprise broadcast of system information related to AS and NAS, paging initiated by 5GC or RAN, establishment, maintenance and release of an RRC connection between the UE and RAN, security functions including key management, establishment, configuration, maintenance and release of Signaling Radio Bearers (SRBs) and Data Radio Bearers (DRBs), mobility functions, QoS management functions, UE measurement reporting and control of the reporting, detection of and recovery from radio link failure, and/or NAS message transfer to/from NAS from/to a UE. In an example, NAS control protocol (e.g. 231 and 251) may be terminated in the wireless device and AMF (e.g. 130) on a network side and may perform functions such as authentication, mobility management between a UE and a AMF for 3GPP access and non-3GPP access, and session management between a UE and a SMF for 3GPP access and non-3GPP access.

In an example, a base station may configure a plurality of logical channels for a wireless device. A logical channel in the plurality of logical channels may correspond to a radio bearer and the radio bearer may be associated with a QoS requirement. In an example, a base station may configure a logical channel to be mapped to one or more TTIs/numerologies in a plurality of TTIs/numerologies. The wireless device may receive a Downlink Control Information (DCI) via Physical Downlink Control CHannel (PDCCH) indicating an uplink grant. In an example, the uplink grant may be for a first TTInumerology and may indicate uplink resources for transmission of a transport block. The base station may configure each logical channel in the plurality of logical channels with one or more parameters to be used by a logical channel prioritization procedure at the MAC layer of the wireless device. The one or more parameters may comprise priority, prioritized bit rate, etc. A logical channel in the plurality of logical channels may correspond to one or more buffers comprising data associated with the logical channel. The logical channel prioritization procedure may allocate the uplink resources to one or more first logical channels in the plurality of logical channels and/or one or more MAC Control Elements (CEs). The one or more first logical channels may be mapped to the first TTI/numerology. The MAC layer at the wireless device may multiplex one or more MAC CEs and/or one or more MAC SDUs (e.g., logical channel) in a MAC PDU (e.g., transport block). In an example, the MAC PDU may comprise a MAC header comprising a plurality of MAC sub-headers. A MAC sub-header in the plurality of MAC sub-headers may correspond to a MAC CE or a MAC SUD (logical channel) in the one or more MAC CEs and/or one or more MAC SDUs. In an example, a MAC CE or a logical channel may be configured with a Logical Channel IDentifier (LCID). In an example, LCID for a logical channel or a MAC CE may be fixed/pre-configured. In an example, LCID for a logical channel or MAC CE may be configured for the wireless device by the base station. The MAC sub-header corresponding to a MAC CE or a MAC SDU may comprise LCID associated with the MAC CE or the MAC SDU.

In an example, a base station may activate and/or deactivate and/or impact one or more processes (e.g., set values of one or more parameters of the one or more processes or start and/or stop one or more timers of the one or more processes) at the wireless device by employing one or more MAC commands. The one or more MAC commands may comprise one or more MAC control elements. In an example, the one or more processes may comprise activation and/or deactivation of PDCP packet duplication for one or more radio bearers. The base station may transmit a MAC CE comprising one or more fields, the values of the fields indicating activation and/or deactivation of PDCP duplication for the one or more radio bearers. In an example, the one or more processes may comprise Channel State Information (CSI) transmission of on one or more cells. The base station may transmit one or more MAC CEs indicating activation and/or deactivation of the CSI transmission on the one or more cells. In an example, the one or more processes may comprise activation or deactivation of one or more secondary cells. In an example, the base station may transmit a MA CE indicating activation or deactivation of one or more secondary cells. In an example, the base station may transmit one or more MAC CEs indicating starting and/or stopping one or more Discontinuous Reception (DRX) timers at the wireless device. In an example, the base station may transmit one or more MAC CEs indicating one or more timing advance values for one or more Timing Advance Groups (TAGs).

FIG. 3 is a block diagram of base stations (base station 1, 120A, and base station 2, 120B) and a wireless device 110. A wireless device may be called an UE. A base station may be called a NB, eNB, gNB, and/or ng-eNB. In an example, a wireless device and/or a base station may act as a relay node. The base station 1, 120A, may comprise at least one communication interface 320A (e.g. a wireless modem, an antenna, a wired modem, and/or the like), at least one processor 321A, and at least one set of program code instructions 323A stored in non-transitory memory 322A and executable by the at least one processor 321A. The base station 2, 120B, may comprise at least one communication interface 320B, at least one processor 321B, and at least one set of program code instructions 323B stored in non-transitory memory 322B and executable by the at least one processor 321B.

A base station may comprise many sectors for example: 1, 2, 3, 4, or 6 sectors. A base station may comprise many cells, for example, ranging from 1 to 50 cells or more. A cell may be categorized, for example, as a primary cell or secondary cell. At Radio Resource Control (RRC) connection establishment/re-establishment/handover, one serving cell may provide the NAS (non-access stratum) mobility information (e.g. Tracking Area Identifier (TAI)). At RRC connection re-establishment/handover, one serving cell may provide the security input. This cell may be referred to as the Primary Cell (PCell). In the downlink, a carrier corresponding to the PCell may be a DL Primary Component Carrier (PCC), while in the uplink, a carrier may be an UL PCC. Depending on wireless device capabilities, Secondary Cells (SCells) may be configured to form together with a PCell a set of serving cells. In a downlink, a carrier corresponding to an SCell may be a downlink secondary component carrier (DL SCC), while in an uplink, a carrier may be an uplink secondary component carrier (UL SCC). An SCell may or may not have an uplink carrier.

A cell, comprising a downlink carrier and optionally an uplink carrier, may be assigned a physical cell ID and a cell index. A carrier (downlink or uplink) may belong to one cell. The cell ID or cell index may also identify the downlink carrier or uplink carrier of the cell (depending on the context it is used). In the disclosure, a cell ID may be equally referred to a carrier ID, and a cell index may be referred to a carrier index. In an implementation, a physical cell ID or a cell index may be assigned to a cell. A cell ID may be determined using a synchronization signal transmitted on a downlink carrier. A cell index may be determined using RRC messages. For example, when the disclosure refers to a first physical cell ID for a first downlink carrier, the disclosure may mean the first physical cell ID is for a cell comprising the first downlink carrier. The same concept may apply to, for example, carrier activation. When the disclosure indicates that a first carrier is activated, the specification may equally mean that a cell comprising the first carrier is activated.

A base station may transmit to a wireless device one or more messages (e.g. RRC messages) comprising a plurality of configuration parameters for one or more cells. One or more cells may comprise at least one primary cell and at least one secondary cell. In an example, an RRC message may be broadcasted or unicasted to the wireless device. In an example, configuration parameters may comprise common parameters and dedicated parameters.

Services and/or functions of an RRC sublayer may comprise at least one of: broadcast of system information related to AS and NAS; paging initiated by 5GC and/or NG-RAN; establishment, maintenance, and/or release of an RRC connection between a wireless device and NG-RAN, which may comprise at least one of addition, modification and release of carrier aggregation; or addition, modification, and/or release of dual connectivity in NR or between E-UTRA and NR. Services and/or functions of an RRC sublayer may further comprise at least one of security functions comprising key management; establishment, configuration, maintenance, and/or release of Signaling Radio Bearers (SRBs) and/or Data Radio Bearers (DRBs); mobility functions which may comprise at least one of a handover (e.g. intra NR mobility or inter-RAT mobility) and a context transfer; or a wireless device cell selection and reselection and control of cell selection and reselection. Services and/or functions of an RRC sublayer may further comprise at least one of QoS management functions; a wireless device measurement configuration/reporting; detection of and/or recovery from radio link failure; or NAS message transfer to/from a core network entity (e.g. AMF, Mobility Management Entity (MME)) from/to the wireless device.

An RRC sublayer may support an RRC_Idle state, an RRC_Inactive state and/or an RRC_Connected state for a wireless device. In an RRC_Idle state, a wireless device may perform at least one of: Public Land Mobile Network (PLMN) selection; receiving broadcasted system information; cell selection/re-selection; monitoring/receiving a paging for mobile terminated data initiated by 5GC; paging for mobile terminated data area managed by 5GC; or DRX for CN paging configured via NAS. In an RRC_Inactive state, a wireless device may perform at least one of: receiving broadcasted system information; cell selection/re-selection; monitoring/receiving a RAN/CN paging initiated by NG-RAN/5GC; RAN-based notification area (RNA) managed by NG-RAN; or DRX for RAN/CN paging configured by NG-RAN/NAS. In an RRC_Idle state of a wireless device, a base station (e.g. NG-RAN) may keep a 5GC-NG-RAN connection (both C/U-planes) for the wireless device; and/or store a UE AS context for the wireless device. In an RRC_Connected state of a wireless device, a base station (e.g. NG-RAN) may perform at least one of: establishment of 5GC-NG-RAN connection (both C/U-planes) for the wireless device; storing a UE AS context for the wireless device; transmit/receive of unicast data to/from the wireless device; or network-controlled mobility based on measurement results received from the wireless device. In an RRC_Connected state of a wireless device, an NG-RAN may know a cell that the wireless device belongs to.

System information (SI) may be divided into minimum SI and other SI. The minimum SI may be periodically broadcast. The minimum SI may comprise basic information required for initial access and information for acquiring any other SI broadcast periodically or provisioned on-demand, i.e. scheduling information. The other SI may either be broadcast, or be provisioned in a dedicated manner, either triggered by a network or upon request from a wireless device. A minimum SI may be transmitted via two different downlink channels using different messages (e.g. MasternformationBlock and SystemInformationBlockType1). Another SI may be transmitted via SystemInformationBlockType2. For a wireless device in an RRC_Connected state, dedicated RRC signaling may be employed for the request and delivery of the other SI. For the wireless device in the RRC_Idle state and/or the RRC_Inactive state, the request may trigger a random-access procedure.

A wireless device may report its radio access capability information which may be static. A base station may request what capabilities for a wireless device to report based on band information. When allowed by a network, a temporary capability restriction request may be sent by the wireless device to signal the limited availability of some capabilities (e.g. due to hardware sharing, interference or overheating) to the base station. The base station may confirm or reject the request. The temporary capability restriction may be transparent to 5GC (e.g., static capabilities may be stored in 5GC).

When CA is configured, a wireless device may have an RRC connection with a network. At RRC connection establishment/re-establishment/handover procedure, one serving cell may provide NAS mobility information, and at RRC connection re-establishment/handover, one serving cell may provide a security input. This cell may be referred to as the PCell. Depending on the capabilities of the wireless device, SCells may be configured to form together with the PCell a set of serving cells. The configured set of serving cells for the wireless device may comprise one PCell and one or more SCells.

The reconfiguration, addition and removal of SCells may be performed by RRC. At intra-NR handover, RRC may also add, remove, or reconfigure SCells for usage with the target PCell. When adding a new SCell, dedicated RRC signaling may be employed to send all required system information of the SCell i.e. while in connected mode, wireless devices may not need to acquire broadcasted system information directly from the SCells.

The purpose of an RRC connection reconfiguration procedure may be to modify an RRC connection, (e.g. to establish, modify and/or release RBs, to perform handover, to setup, modify, and/or release measurements, to add, modify, and/or release SCells and cell groups). As part of the RRC connection reconfiguration procedure, NAS dedicated information may be transferred from the network to the wireless device. The RRCConnectionReconfiguration message may be a command to modify an RRC connection. It may convey information for measurement configuration, mobility control, radio resource configuration (e.g. RBs, MAC main configuration and physical channel configuration) comprising any associated dedicated NAS information and security configuration. If the received RRC Connection Reconfiguration message includes the sCellToReleaseList, the wireless device may perform an SCell release. If the received RRC Connection Reconfiguration message includes the sCellToAddModList, the wireless device may perform SCell additions or modification.

An RRC connection establishment (or reestablishment, resume) procedure may be to establish (or reestablish, resume) an RRC connection. an RRC connection establishment procedure may comprise SRB1 establishment. The RRC connection establishment procedure may be used to transfer the initial NAS dedicated information/message from a wireless device to E-UTRAN. The RRCConnectionReestablishment message may be used to reestablish SRB1.

A measurement report procedure may be to transfer measurement results from a wireless device to NG-RAN. The wireless device may initiate a measurement report procedure after successful security activation. A measurement report message may be employed to transmit measurement results.

The wireless device 110 may comprise at least one communication interface 310 (e.g. a wireless modem, an antenna, and/or the like), at least one processor 314, and at least one set of program code instructions 316 stored in non-transitory memory 315 and executable by the at least one processor 314. The wireless device 110 may further comprise at least one of at least one speaker/microphone 311, at least one keypad 312, at least one display/touchpad 313, at least one power source 317, at least one global positioning system (GPS) chipset 318, and other peripherals 319.

The processor 314 of the wireless device 110, the processor 321A of the base station 1 120A, and/or the processor 321B of the base station 2 120B may comprise at least one of a general-purpose processor, a digital signal processor (DSP), a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) and/or other programmable logic device, discrete gate and/or transistor logic, discrete hardware components, and the like. The processor 314 of the wireless device 110, the processor 321A in base station 1 120A, and/or the processor 321B in base station 2 120B may perform at least one of signal coding/processing, data processing, power control, input/output processing, and/or any other functionality that may enable the wireless device 110, the base station 1 120A and/or the base station 2 120B to operate in a wireless environment.

The processor 314 of the wireless device 110 may be connected to the speaker/microphone 311, the keypad 312, and/or the display/touchpad 313. The processor 314 may receive user input data from and/or provide user output data to the speaker/microphone 311, the keypad 312, and/or the display/touchpad 313. The processor 314 in the wireless device 110 may receive power from the power source 317 and/or may be configured to distribute the power to the other components in the wireless device 110. The power source 317 may comprise at least one of one or more dry cell batteries, solar cells, fuel cells, and the like. The processor 314 may be connected to the GPS chipset 318. The GPS chipset 318 may be configured to provide geographic location information of the wireless device 110.

The processor 314 of the wireless device 110 may further be connected to other peripherals 319, which may comprise one or more software and/or hardware modules that provide additional features and/or functionalities. For example, the peripherals 319 may comprise at least one of an accelerometer, a satellite transceiver, a digital camera, a universal serial bus (USB) port, a hands-free headset, a frequency modulated (FM) radio unit, a media player, an Internet browser, and the like.

The communication interface 320A of the base station 1, 120A, and/or the communication interface 320B of the base station 2, 120B, may be configured to communicate with the communication interface 310 of the wireless device 110 via a wireless link 330A and/or a wireless link 330B respectively. In an example, the communication interface 320A of the base station 1, 120A, may communicate with the communication interface 320B of the base station 2 and other RAN and core network nodes.

The wireless link 330A and/or the wireless link 330B may comprise at least one of a bi-directional link and/or a directional link. The communication interface 310 of the wireless device 110 may be configured to communicate with the communication interface 320A of the base station 1 120A and/or with the communication interface 320B of the base station 2 120B. The base station 1 120A and the wireless device 110 and/or the base station 2 120B and the wireless device 110 may be configured to send and receive transport blocks via the wireless link 330A and/or via the wireless link 330B, respectively. The wireless link 330A and/or the wireless link 330B may employ at least one frequency carrier. According to some of various aspects of embodiments, transceiver(s) may be employed. A transceiver may be a device that comprises both a transmitter and a receiver. Transceivers may be employed in devices such as wireless devices, base stations, relay nodes, and/or the like. Example embodiments for radio technology implemented in the communication interface 310, 320A, 320B and the wireless link 330A, 330B are illustrated in FIG. 4A, FIG. 4B, FIG. 4C, FIG. 4D, FIG. 6, FIG. 7A, FIG. 7B, FIG. 8, and associated text.

In an example, other nodes in a wireless network (e.g. AMF, UPF, SMF, etc.) may comprise one or more communication interfaces, one or more processors, and memory storing instructions.

A node (e.g. wireless device, base station, AMF, SMF, UPF, servers, switches, antennas, and/or the like) may comprise one or more processors, and memory storing instructions that when executed by the one or more processors causes the node to perform certain processes and/or functions. Example embodiments may enable operation of single-carrier and/or multi-carrier communications. Other example embodiments may comprise a non-transitory tangible computer readable media comprising instructions executable by one or more processors to cause operation of single-carrier and/or multi-carrier communications. Yet other example embodiments may comprise an article of manufacture that comprises a non-transitory tangible computer readable machine-accessible medium having instructions encoded thereon for enabling programmable hardware to cause a node to enable operation of single-carrier and/or multi-carrier communications. The node may include processors, memory, interfaces, and/or the like.

An interface may comprise at least one of a hardware interface, a firmware interface, a software interface, and/or a combination thereof. The hardware interface may comprise connectors, wires, electronic devices such as drivers, amplifiers, and/or the like. The software interface may comprise code stored in a memory device to implement protocol(s), protocol layers, communication drivers, device drivers, combinations thereof, and/or the like. The firmware interface may comprise a combination of embedded hardware and code stored in and/or in communication with a memory device to implement connections, electronic device operations, protocol(s), protocol layers, communication drivers, device drivers, hardware operations, combinations thereof, and/or the like.

FIG. 4A, FIG. 4B, FIG. 4C and FIG. 4D are example diagrams for uplink and downlink signal transmission as per an aspect of an embodiment of the present disclosure. FIG. 4A shows an example uplink transmitter for at least one physical channel. A baseband signal representing a physical uplink shared channel may perform one or more functions. The one or more functions may comprise at least one of: scrambling; modulation of scrambled bits to generate complex-valued symbols; mapping of the complex-valued modulation symbols onto one or several transmission layers; transform precoding to generate complex-valued symbols; precoding of the complex-valued symbols; mapping of precoded complex-valued symbols to resource elements; generation of complex-valued time-domain Single Carrier-Frequency Division Multiple Access (SC-FDMA) or CP-OFDM signal for an antenna port; and/or the like. In an example, when transform precoding is enabled, a SC-FDMA signal for uplink transmission may be generated. In an example, when transform precoding is not enabled, an CP-OFDM signal for uplink transmission may be generated by FIG. 4A. These functions are illustrated as examples and it is anticipated that other mechanisms may be implemented in various embodiments.

An example structure for modulation and up-conversion to the carrier frequency of the complex-valued SC-FDMA or CP-OFDM baseband signal for an antenna port and/or the complex-valued Physical Random Access CHannel (PRACH) baseband signal is shown in FIG. 4B. Filtering may be employed prior to transmission.

An example structure for downlink transmissions is shown in FIG. 4C. The baseband signal representing a downlink physical channel may perform one or more functions. The one or more functions may comprise: scrambling of coded bits in a codeword to be transmitted on a physical channel; modulation of scrambled bits to generate complex-valued modulation symbols; mapping of the complex-valued modulation symbols onto one or several transmission layers; precoding of the complex-valued modulation symbols on a layer for transmission on the antenna ports; mapping of complex-valued modulation symbols for an antenna port to resource elements; generation of complex-valued time-domain OFDM signal for an antenna port; and/or the like. These functions are illustrated as examples and it is anticipated that other mechanisms may be implemented in various embodiments.

In an example, a gNB may transmit a first symbol and a second symbol on an antenna port, to a wireless device. The wireless device may infer the channel (e.g., fading gain, multipath delay, etc.) for conveying the second symbol on the antenna port, from the channel for conveying the first symbol on the antenna port. In an example, a first antenna port and a second antenna port may be quasi co-located if one or more large-scale properties of the channel over which a first symbol on the first antenna port is conveyed may be inferred from the channel over which a second symbol on a second antenna port is conveyed. The one or more large-scale properties may comprise at least one of: delay spread; doppler spread; doppler shift; average gain; average delay; and/or spatial Receiving (Rx) parameters.

An example modulation and up-conversion to the carrier frequency of the complex-valued OFDM baseband signal for an antenna port is shown in FIG. 4D. Filtering may be employed prior to transmission.

FIG. 5A is a diagram of an example uplink channel mapping and example uplink physical signals. FIG. 5B is a diagram of an example downlink channel mapping and a downlink physical signals. In an example, a physical layer may provide one or more information transfer services to a MAC and/or one or more higher layers. For example, the physical layer may provide the one or more information transfer services to the MAC via one or more transport channels. An information transfer service may indicate how and with what characteristics data are transferred over the radio interface.

In an example embodiment, a radio network may comprise one or more downlink and/or uplink transport channels. For example, a diagram in FIG. 5A shows example uplink transport channels comprising Uplink-Shared CHannel (UL-SCH) 501 and Random Access CHannel (RACH) 502. A diagram in FIG. 5B shows example downlink transport channels comprising Downlink-Shared CHannel (DL-SCH) 511, Paging CHannel (PCH) 512, and Broadcast CHannel (BCH) 513. A transport channel may be mapped to one or more corresponding physical channels. For example, UL-SCH 501 may be mapped to Physical Uplink Shared CHannel (PUSCH) 503. RACH 502 may be mapped to PRACH 505. DL-SCH 511 and PCH 512 may be mapped to Physical Downlink Shared CHannel (PDSCH) 514. BCH 513 may be mapped to Physical Broadcast CHannel (PBCH) 516.

There may be one or more physical channels without a corresponding transport channel. The one or more physical channels may be employed for Uplink Control Information (UCI) 509 and/or Downlink Control Information (DCI) 517. For example, Physical Uplink Control CHannel (PUCCH) 504 may carry UCI 509 from a UE to a base station. For example, Physical Downlink Control CHannel (PDCCH) 515 may carry DCI 517 from a base station to a UE. NR may support UCI 509 multiplexing in PUSCH 503 when UCI 509 and PUSCH 503 transmissions may coincide in a slot at least in part. The UCI 509 may comprise at least one of CSI, Acknowledgement (ACK)/Negative Acknowledgement (NACK), and/or scheduling request. The DCI 517 on PDCCH 515 may indicate at least one of following: one or more downlink assignments and/or one or more uplink scheduling grants

In uplink, a UE may transmit one or more Reference Signals (RSs) to a base station. For example, the one or more RSs may be at least one of Demodulation-RS (DM-RS) 506, Phase Tracking-RS (PT-RS) 507, and/or Sounding RS (SRS) 508. In downlink, a base station may transmit (e.g., unicast, multicast, and/or broadcast) one or more RSs to a UE. For example, the one or more RSs may be at least one of Primary Synchronization Signal (PSS)/Secondary Synchronization Signal (SSS) 521, CSI-RS 522, DM-RS 523, and/or PT-RS 524.

In an example, a UE may transmit one or more uplink DM-RSs 506 to a base station for channel estimation, for example, for coherent demodulation of one or more uplink physical channels (e.g., PUSCH 503 and/or PUCCH 504). For example, a UE may transmit a base station at least one uplink DM-RS 506 with PUSCH 503 and/or PUCCH 504, wherein the at least one uplink DM-RS 506 may be spanning a same frequency range as a corresponding physical channel. In an example, a base station may configure a UE with one or more uplink DM-RS configurations. At least one DM-RS configuration may support a front-loaded DM-RS pattern. A front-loaded DM-RS may be mapped over one or more OFDM symbols (e.g., 1 or 2 adjacent OFDM symbols). One or more additional uplink DM-RS may be configured to transmit at one or more symbols of a PUSCH and/or PUCCH. A base station may semi-statistically configure a UE with a maximum number of front-loaded DM-RS symbols for PUSCH and/or PUCCH. For example, a UE may schedule a single-symbol DM-RS and/or double symbol DM-RS based on a maximum number of front-loaded DM-RS symbols, wherein a base station may configure the UE with one or more additional uplink DM-RS for PUSCH and/or PUCCH. A new radio network may support, e.g., at least for CP-OFDM, a common DM-RS structure for DL and UL, wherein a DM-RS location, DM-RS pattern, and/or scrambling sequence may be same or different.

In an example, whether uplink PT-RS 507 is present or not may depend on a RRC configuration. For example, a presence of uplink PT-RS may be UE-specifically configured. For example, a presence and/or a pattern of uplink PT-RS 507 in a scheduled resource may be UE-specifically configured by a combination of RRC signaling and/or association with one or more parameters employed for other purposes (e.g., Modulation and Coding Scheme (MCS)) which may be indicated by DCI. When configured, a dynamic presence of uplink PT-RS 507 may be associated with one or more DCI parameters comprising at least MCS. A radio network may support plurality of uplink PT-RS densities defined in time/frequency domain. When present, a frequency domain density may be associated with at least one configuration of a scheduled bandwidth. A UE may assume a same precoding for a DMRS port and a PT-RS port. A number of PT-RS ports may be fewer than a number of DM-RS ports in a scheduled resource. For example, uplink PT-RS 507 may be confined in the scheduled time/frequency duration for a UE.

In an example, a UE may transmit SRS 508 to a base station for channel state estimation to support uplink channel dependent scheduling and/or link adaptation. For example, SRS 508 transmitted by a UE may allow for a base station to estimate an uplink channel state at one or more different frequencies. A base station scheduler may employ an uplink channel state to assign one or more resource blocks of good quality for an uplink PUSCH transmission from a UE. A base station may semi-statistically configure a UE with one or more SRS resource sets. For an SRS resource set, a base station may configure a UE with one or more SRS resources. An SRS resource set applicability may be configured by a higher layer (e.g., RRC) parameter. For example, when a higher layer parameter indicates beam management, a SRS resource in each of one or more SRS resource sets may be transmitted at a time instant. A UE may transmit one or more SRS resources in different SRS resource sets simultaneously. A new radio network may support aperiodic, periodic and/or semi-persistent SRS transmissions. A UE may transmit SRS resources based on one or more trigger types, wherein the one or more trigger types may comprise higher layer signaling (e.g., RRC) and/or one or more DCI formats (e.g., at least one DCI format may be employed for a UE to select at least one of one or more configured SRS resource sets. An SRS trigger type 0 may refer to an SRS triggered based on a higher layer signaling. An SRS trigger type 1 may refer to an SRS triggered based on one or more DCI formats. In an example, when PUSCH 503 and SRS 508 are transmitted in a same slot, a UE may be configured to transmit SRS 508 after a transmission of PUSCH 503 and corresponding uplink DM-RS 506.

In an example, a base station may semi-statistically configure a UE with one or more SRS configuration parameters indicating at least one of following: a SRS resource configuration identifier, a number of SRS ports, time domain behavior of SRS resource configuration (e.g., an indication of periodic, semi-persistent, or aperiodic SRS), slot (mini-slot, and/or subframe) level periodicity and/or offset for a periodic and/or aperiodic SRS resource, a number of OFDM symbols in a SRS resource, starting OFDM symbol of a SRS resource, a SRS bandwidth, a frequency hopping bandwidth, a cyclic shift, and/or a SRS sequence ID.

In an example, in a time domain, an SS/PBCH block may comprise one or more OFDM symbols (e.g., 4 OFDM symbols numbered in increasing order from 0 to 3) within the SS/PBCH block. An SS/PBCH block may comprise PSS/SSS 521 and PBCH 516. In an example, in the frequency domain, an SS/PBCH block may comprise one or more contiguous subcarriers (e.g., 240 contiguous subcarriers with the subcarriers numbered in increasing order from 0 to 239) within the SS/PBCH block. For example, a PSS/SSS 521 may occupy 1 OFDM symbol and 127 subcarriers. For example, PBCH 516 may span across 3 OFDM symbols and 240 subcarriers. A UE may assume that one or more SS/PBCH blocks transmitted with a same block index may be quasi co-located, e.g., with respect to Doppler spread, Doppler shift, average gain, average delay, and spatial Rx parameters. A UE may not assume quasi co-location for other SS/PBCH block transmissions. A periodicity of an SS/PBCH block may be configured by a radio network (e.g., by an RRC signaling) and one or more time locations where the SS/PBCH block may be sent may be determined by sub-carrier spacing. In an example, a UE may assume a band-specific sub-carrier spacing for an SS/PBCH block unless a radio network has configured a UE to assume a different sub-carrier spacing.

In an example, downlink CSI-RS 522 may be employed for a UE to acquire channel state information. A radio network may support periodic, aperiodic, and/or semi-persistent transmission of downlink CSI-RS 522. For example, a base station may semi-statistically configure and/or reconfigure a UE with periodic transmission of downlink CSI-RS 522. A configured CSI-RS resources may be activated ad/or deactivated. For semi-persistent transmission, an activation and/or deactivation of CSI-RS resource may be triggered dynamically. In an example, CSI-RS configuration may comprise one or more parameters indicating at least a number of antenna ports. For example, a base station may configure a UE with 32 ports. A base station may semi-statistically configure a UE with one or more CSI-RS resource sets. One or more CSI-RS resources may be allocated from one or more CSI-RS resource sets to one or more UEs. For example, a base station may semi-statistically configure one or more parameters indicating CSI RS resource mapping, for example, time-domain location of one or more CSI-RS resources, a bandwidth of a CSI-RS resource, and/or a periodicity. In an example, a UE may be configured to employ a same OFDM symbols for downlink CSI-RS 522 and control resource set (coreset) when the downlink CSI-RS 522 and coreset are spatially quasi co-located and resource elements associated with the downlink CSI-RS 522 are the outside of PRBs configured for coreset. In an example, a UE may be configured to employ a same OFDM symbols for downlink CSI-RS 522 and SSB/PBCH when the downlink CSI-RS 522 and SSB/PBCH are spatially quasi co-located and resource elements associated with the downlink CSI-RS 522 are the outside of PRBs configured for SSB/PBCH.

In an example, a UE may transmit one or more downlink DM-RSs 523 to a base station for channel estimation, for example, for coherent demodulation of one or more downlink physical channels (e.g., PDSCH 514). For example, a radio network may support one or more variable and/or configurable DM-RS patterns for data demodulation. At least one downlink DM-RS configuration may support a front-loaded DM-RS pattern. A front-loaded DM-RS may be mapped over one or more OFDM symbols (e.g., 1 or 2 adjacent OFDM symbols). A base station may semi-statistically configure a UE with a maximum number of front-loaded DM-RS symbols for PDSCH 514. For example, a DM-RS configuration may support one or more DM-RS ports. For example, for single user-MIMO, a DM-RS configuration may support at least 8 orthogonal downlink DM-RS ports. For example, for multiuser-MIMO, a DM-RS configuration may support 12 orthogonal downlink DM-RS ports. A radio network may support, e.g., at least for CP-OFDM, a common DM-RS structure for DL and UL, wherein a DM-RS location, DM-RS pattern, and/or scrambling sequence may be same or different.

In an example, whether downlink PT-RS 524 is present or not may depend on a RRC configuration. For example, a presence of downlink PT-RS 524 may be UE-specifically configured. For example, a presence and/or a pattern of downlink PT-RS 524 in a scheduled resource may be UE-specifically configured by a combination of RRC signaling and/or association with one or more parameters employed for other purposes (e.g., MCS) which may be indicated by DCI. When configured, a dynamic presence of downlink PT-RS 524 may be associated with one or more DCI parameters comprising at least MCS. A radio network may support plurality of PT-RS densities defined in time/frequency domain. When present, a frequency domain density may be associated with at least one configuration of a scheduled bandwidth. A UE may assume a same precoding for a DMRS port and a PT-RS port. A number of PT-RS ports may be fewer than a number of DM-RS ports in a scheduled resource. For example, downlink PT-RS 524 may be confined in the scheduled time/frequency duration for a UE.

FIG. 6 is a diagram depicting an example frame structure for a carrier as per an aspect of an embodiment of the present disclosure. A multicarrier OFDM communication system may include one or more carriers, for example, ranging from 1 to 32 carriers, in case of carrier aggregation, or ranging from 1 to 64 carriers, in case of dual connectivity. Different radio frame structures may be supported (e.g., for FDD and for TDD duplex mechanisms). FIG. 6 shows an example frame structure. Downlink and uplink transmissions may be organized into radio frames 601. In this example, radio frame duration is 10 ms. In this example, a 10 ms radio frame 601 may be divided into ten equally sized subframes 602 with 1 ms duration. Subframe(s) may comprise one or more slots (e.g. slots 603 and 605) depending on subcarrier spacing and/or CP length. For example, a subframe with 15 kHz, 30 kHz, 60 kHz, 120 kHz, 240 kHz and 480 kHz subcarrier spacing may comprise one, two, four, eight, sixteen and thirty-two slots, respectively. In FIG. 6, a subframe may be divided into two equally sized slots 603 with 0.5 ms duration. For example, 10 subframes may be available for downlink transmission and 10 subframes may be available for uplink transmissions in a 10 ms interval. Uplink and downlink transmissions may be separated in the frequency domain. Slot(s) may include a plurality of OFDM symbols 604. The number of OFDM symbols 604 in a slot 605 may depend on the cyclic prefix length. For example, a slot may be 14 OFDM symbols for the same subcarrier spacing of up to 480 kHz with normal CP. A slot may be 12 OFDM symbols for the same subcarrier spacing of 60 kHz with extended CP. A slot may contain downlink, uplink, or a downlink part and an uplink part and/or alike.

FIG. 7A is a diagram depicting example sets of OFDM subcarriers as per an aspect of an embodiment of the present disclosure. In the example, a gNB may communicate with a wireless device with a carrier with an example channel bandwidth 700. Arrow(s) in the diagram may depict a subcarrier in a multicarrier OFDM system. The OFDM system may use technology such as OFDM technology, SC-FDMA technology, and/or the like. In an example, an arrow 701 shows a subcarrier transmitting information symbols. In an example, a subcarrier spacing 702, between two contiguous subcarriers in a carrier, may be any one of 15 KHz, 30 KHz, 60 KHz, 120 KHz, 240 KHz etc. In an example, different subcarrier spacing may correspond to different transmission numerologies. In an example, a transmission numerology may comprise at least: a numerology index; a value of subcarrier spacing; a type of cyclic prefix (CP). In an example, a gNB may transmit to/receive from a UE on a number of subcarriers 703 in a carrier. In an example, a bandwidth occupied by a number of subcarriers 703 (transmission bandwidth) may be smaller than the channel bandwidth 700 of a carrier, due to guard band 704 and 705. In an example, a guard band 704 and 705 may be used to reduce interference to and from one or more neighbor carriers. A number of subcarriers (transmission bandwidth) in a carrier may depend on the channel bandwidth of the carrier and the subcarrier spacing. For example, a transmission bandwidth, for a carrier with 20 MHz channel bandwidth and 15 KHz subcarrier spacing, may be in number of 1024 subcarriers.

In an example, a gNB and a wireless device may communicate with multiple CCs when configured with CA. In an example, different component carriers may have different bandwidth and/or subcarrier spacing, if CA is supported. In an example, a gNB may transmit a first type of service to a UE on a first component carrier. The gNB may transmit a second type of service to the UE on a second component carrier. Different type of services may have different service requirement (e.g., data rate, latency, reliability), which may be suitable for transmission via different component carrier having different subcarrier spacing and/or bandwidth. FIG. 7B shows an example embodiment. A first component carrier may comprise a first number of subcarriers 706 with a first subcarrier spacing 709. A second component carrier may comprise a second number of subcarriers 707 with a second subcarrier spacing 710. A third component carrier may comprise a third number of subcarriers 708 with a third subcarrier spacing 711. Carriers in a multicarrier OFDM communication system may be contiguous carriers, non-contiguous carriers, or a combination of both contiguous and non-contiguous carriers.

FIG. 8 is a diagram depicting OFDM radio resources as per an aspect of an embodiment of the present disclosure. In an example, a carrier may have a transmission bandwidth 801. In an example, a resource grid may be in a structure of frequency domain 802 and time domain 803. In an example, a resource grid may comprise a first number of OFDM symbols in a subframe and a second number of resource blocks, starting from a common resource block indicated by higher-layer signaling (e.g. RRC signaling), for a transmission numerology and a carrier. In an example, in a resource grid, a resource unit identified by a subcarrier index and a symbol index may be a resource element 805. In an example, a subframe may comprise a first number of OFDM symbols 807 depending on a numerology associated with a carrier. For example, when a subcarrier spacing of a numerology of a carrier is 15 KHz, a subframe may have 14 OFDM symbols for a carrier. When a subcarrier spacing of a numerology is 30 KHz, a subframe may have 28 OFDM symbols. When a subcarrier spacing of a numerology is 60 Khz, a subframe may have 56 OFDM symbols, etc. In an example, a second number of resource blocks comprised in a resource grid of a carrier may depend on a bandwidth and a numerology of the carrier.

As shown in FIG. 8, a resource block 806 may comprise 12 subcarriers. In an example, multiple resource blocks may be grouped into a Resource Block Group (RBG) 804. In an example, a size of a RBG may depend on at least one of: a RRC message indicating a RBG size configuration; a size of a carrier bandwidth; or a size of a bandwidth part of a carrier. In an example, a carrier may comprise multiple bandwidth parts. A first bandwidth part of a carrier may have different frequency location and/or bandwidth from a second bandwidth part of the carrier.

In an example, a gNB may transmit a downlink control information comprising a downlink or uplink resource block assignment to a wireless device. A base station may transmit to or receive from, a wireless device, data packets (e.g. transport blocks) scheduled and transmitted via one or more resource blocks and one or more slots according to parameters in a downlink control information and/or RRC message(s). In an example, a starting symbol relative to a first slot of the one or more slots may be indicated to the wireless device. In an example, a gNB may transmit to or receive from, a wireless device, data packets scheduled on one or more RBGs and one or more slots.

In an example, a gNB may transmit a downlink control information comprising a downlink assignment to a wireless device via one or more PDCCHs. The downlink assignment may comprise parameters indicating at least modulation and coding format; resource allocation; and/or HARQ information related to DL-SCH. In an example, a resource allocation may comprise parameters of resource block allocation; and/or slot allocation. In an example, a gNB may dynamically allocate resources to a wireless device via a Cell-Radio Network Temporary Identifier (C-RNTI) on one or more PDCCHs. The wireless device may monitor the one or more PDCCHs in order to find possible allocation when its downlink reception is enabled. The wireless device may receive one or more downlink data package on one or more PDSCH scheduled by the one or more PDCCHs, when successfully detecting the one or more PDCCHs.

In an example, a gNB may allocate Configured Scheduling (CS) resources for down link transmission to a wireless device. The gNB may transmit one or more RRC messages indicating a periodicity of the CS grant. The gNB may transmit a DCI via a PDCCH addressed to a Configured Scheduling-RNTI (CS-RNTI) activating the CS resources. The DCI may comprise parameters indicating that the downlink grant is a CS grant. The CS grant may be implicitly reused according to the periodicity defined by the one or more RRC messages, until deactivated.

In an example, a gNB may transmit a downlink control information comprising an uplink grant to a wireless device via one or more PDCCHs. The uplink grant may comprise parameters indicating at least modulation and coding format; resource allocation; and/or HARQ information related to UL-SCH. In an example, a resource allocation may comprise parameters of resource block allocation; and/or slot allocation. In an example, a gNB may dynamically allocate resources to a wireless device via a C-RNTI on one or more PDCCHs. The wireless device may monitor the one or more PDCCHs in order to find possible resource allocation. The wireless device may transmit one or more uplink data package via one or more PUSCH scheduled by the one or more PDCCHs, when successfully detecting the one or more PDCCHs.

In an example, a gNB may allocate CS resources for uplink data transmission to a wireless device. The gNB may transmit one or more RRC messages indicating a periodicity of the CS grant. The gNB may transmit a DCI via a PDCCH addressed to a CS-RNTI activating the CS resources. The DCI may comprise parameters indicating that the uplink grant is a CS grant. The CS grant may be implicitly reused according to the periodicity defined by the one or more RRC message, until deactivated.

In an example, a base station may transmit DCI/control signaling via PDCCH. The DCI may take a format in a plurality of formats. A DCI may comprise downlink and/or uplink scheduling information (e.g., resource allocation information, HARQ related parameters, MCS), request for CSI (e.g., aperiodic CQI reports), request for SRS, uplink power control commands for one or more cells, one or more timing information (e.g., TB transmission/reception timing, HARQ feedback timing, etc.), etc. In an example, a DCI may indicate an uplink grant comprising transmission parameters for one or more transport blocks. In an example, a DCI may indicate downlink assignment indicating parameters for receiving one or more transport blocks. In an example, a DCI may be used by base station to initiate a contention-free random access at the wireless device. In an example, the base station may transmit a DCI comprising slot format indicator (SFI) notifying a slot format. In an example, the base station may transmit a DCI comprising pre-emption indication notifying the PRB(s) and/or OFDM symbol(s) where a UE may assume no transmission is intended for the UE. In an example, the base station may transmit a DCI for group power control of PUCCH or PUSCH or SRS. In an example, a DCI may correspond to an RNTI. In an example, the wireless device may obtain an RNTI in response to completing the initial access (e.g., C-RNTI). In an example, the base station may configure an RNTI for the wireless (e.g., CS-RNTI, TPC-CS-RNTI, TPC-PUCCH-RNTI, TPC-PUSCH-RNTI, TPC-SRS-RNTI). In an example, the wireless device may compute an RNTI (e.g., the wireless device may compute RA-RNTI based on resources used for transmission of a preamble). In an example, an RNTI may have a pre-configured value (e.g., P-RNTI or SI-RNTI). In an example, a wireless device may monitor a group common search space which may be used by base station for transmitting DCIs that are intended for a group of UEs. In an example, a group common DCI may correspond to an RNTI which is commonly configured for a group of UEs. In an example, a wireless device may monitor a UE-specific search space. In an example, a UE specific DCI may correspond to an RNTI configured for the wireless device.

A NR system may support a single beam operation and/or a multi-beam operation. In a multi-beam operation, a base station may perform a downlink beam sweeping to provide coverage for common control channels and/or downlink SS blocks, which may comprise at least a PSS, a SSS, and/or PBCH. A wireless device may measure quality of a beam pair link using one or more RSs. One or more SS blocks, or one or more CSI-RS resources, associated with a CSI-RS resource index (CRI), or one or more DM-RSs of PBCH, may be used as RS for measuring quality of a beam pair link. Quality of a beam pair link may be defined as a reference signal received power (RSRP) value, or a reference signal received quality (RSRQ) value, and/or a CSI value measured on RS resources. The base station may indicate whether an RS resource, used for measuring a beam pair link quality, is quasi-co-located (QCLed) with DM-RSs of a control channel. A RS resource and DM-RSs of a control channel may be called QCLed when a channel characteristics from a transmission on an RS to a wireless device, and that from a transmission on a control channel to a wireless device, are similar or same under a configured criterion. In a multi-beam operation, a wireless device may perform an uplink beam sweeping to access a cell.

In an example, a wireless device may be configured to monitor PDCCH on one or more beam pair links simultaneously depending on a capability of a wireless device. This may increase robustness against beam pair link blocking. A base station may transmit one or more messages to configure a wireless device to monitor PDCCH on one or more beam pair links in different PDCCH OFDM symbols. For example, a base station may transmit higher layer signaling (e.g. RRC signaling) or MAC CE comprising parameters related to the Rx beam setting of a wireless device for monitoring PDCCH on one or more beam pair links. A base station may transmit indication of spatial QCL assumption between an DL RS antenna port(s) (for example, cell-specific CSI-RS, or wireless device-specific CSI-RS, or SS block, or PBCH with or without DM-RSs of PBCH), and DL RS antenna port(s) for demodulation of DL control channel. Signaling for beam indication for a PDCCH may be MAC CE signaling, or RRC signaling, or DCI signaling, or specification-transparent and/or implicit method, and combination of these signaling methods.

For reception of unicast DL data channel, a base station may indicate spatial QCL parameters between DL RS antenna port(s) and DM-RS antenna port(s) of DL data channel. The base station may transmit DCI (e.g. downlink grants) comprising information indicating the RS antenna port(s). The information may indicate RS antenna port(s) which may be QCLed with the DM-RS antenna port(s). Different set of DM-RS antenna port(s) for a DL data channel may be indicated as QCL with different set of the RS antenna port(s).

FIG. 9A is an example of beam sweeping in a DL channel. In an RRC_INACTIVE state or RRC_IDLE state, a wireless device may assume that SS blocks form an SS burst 940, and an SS burst set 950. The SS burst set 950 may have a given periodicity. For example, in a multi-beam operation, a base station 120 may transmit SS blocks in multiple beams, together forming a SS burst 940. One or more SS blocks may be transmitted on one beam. If multiple SS bursts 940 are transmitted with multiple beams, SS bursts together may form SS burst set 950.

A wireless device may further use CSI-RS in the multi-beam operation for estimating a beam quality of a links between a wireless device and a base station. A beam may be associated with a CSI-RS. For example, a wireless device may, based on a RSRP measurement on CSI-RS, report a beam index, as indicated in a CRI for downlink beam selection, and associated with a RSRP value of a beam. A CSI-RS may be transmitted on a CSI-RS resource including at least one of one or more antenna ports, one or more time or frequency radio resources. A CSI-RS resource may be configured in a cell-specific way by common RRC signaling, or in a wireless device-specific way by dedicated RRC signaling, and/or L1/L2 signaling. Multiple wireless devices covered by a cell may measure a cell-specific CSI-RS resource. A dedicated subset of wireless devices covered by a cell may measure a wireless device-specific CSI-RS resource.

A CSI-RS resource may be transmitted periodically, or using aperiodic transmission, or using a multi-shot or semi-persistent transmission. For example, in a periodic transmission in FIG. 9A, a base station 120 may transmit configured CSI-RS resources 940 periodically using a configured periodicity in a time domain. In an aperiodic transmission, a configured CSI-RS resource may be transmitted in a dedicated time slot. In a multi-shot or semi-persistent transmission, a configured CSI-RS resource may be transmitted within a configured period. Beams used for CSI-RS transmission may have different beam width than beams used for SS-blocks transmission.

FIG. 9B is an example of a beam management procedure in an example new radio network. A base station 120 and/or a wireless device 110 may perform a downlink L1/L2 beam management procedure. One or more of the following downlink L1/L2 beam management procedures may be performed within one or more wireless devices 110 and one or more base stations 120. In an example, a P-1 procedure 910 may be used to enable the wireless device 110 to measure one or more Transmission (Tx) beams associated with the base station 120 to support a selection of a first set of Tx beams associated with the base station 120 and a first set of Rx beam(s) associated with a wireless device 110. For beamforming at a base station 120, a base station 120 may sweep a set of different TX beams. For beamforming at a wireless device 110, a wireless device 110 may sweep a set of different Rx beams. In an example, a P-2 procedure 920 may be used to enable a wireless device 110 to measure one or more Tx beams associated with a base station 120 to possibly change a first set of Tx beams associated with a base station 120. A P-2 procedure 920 may be performed on a possibly smaller set of beams for beam refinement than in the P-1 procedure 910. A P-2 procedure 920 may be a special case of a P-1 procedure 910. In an example, a P-3 procedure 930 may be used to enable a wireless device 110 to measure at least one Tx beam associated with a base station 120 to change a first set of Rx beams associated with a wireless device 110.

A wireless device 110 may transmit one or more beam management reports to a base station 120. In one or more beam management reports, a wireless device 110 may indicate some beam pair quality parameters, comprising at least, one or more beam identifications; RSRP; Precoding Matrix Indicator (PMI)/Channel Quality Indicator (CQI)/Rank Indicator (RI) of a subset of configured beams. Based on one or more beam management reports, a base station 120 may transmit to a wireless device 110 a signal indicating that one or more beam pair links are one or more serving beams. A base station 120 may transmit PDCCH and PDSCH for a wireless device 110 using one or more serving beams.

In an example embodiment, new radio network may support a Bandwidth Adaptation (BA). In an example, receive and/or transmit bandwidths configured by an UE employing a BA may not be large. For example, a receive and/or transmit bandwidths may not be as large as a bandwidth of a cell. Receive and/or transmit bandwidths may be adjustable. For example, a UE may change receive and/or transmit bandwidths, e.g., to shrink during period of low activity to save power. For example, a UE may change a location of receive and/or transmit bandwidths in a frequency domain, e.g. to increase scheduling flexibility. For example, a UE may change a subcarrier spacing, e.g. to allow different services.

In an example embodiment, a subset of a total cell bandwidth of a cell may be referred to as a Bandwidth Part (BWP). A base station may configure a UE with one or more BWPs to achieve a BA. For example, a base station may indicate, to a UE, which of the one or more (configured) BWPs is an active BWP.

FIG. 10 is an example diagram of 3 BWPs configured: BWP1 (1010 and 1050) with a width of 40 MHz and subcarrier spacing of 15 kHz; BWP2 (1020 and 1040) with a width of 10 MHz and subcarrier spacing of 15 kHz; BWP3 1030 with a width of 20 MHz and subcarrier spacing of 60 kHz.

In an example, a UE, configured for operation in one or more BWPs of a cell, may be configured by one or more higher layers (e.g. RRC layer) for a cell a set of one or more BWPs (e.g., at most four BWPs) for receptions by the UE (DL BWP set) in a DL bandwidth by at least one parameter DL-BWP and a set of one or more BWPs (e.g., at most four BWPs) for transmissions by a UE (UL BWP set) in an UL bandwidth by at least one parameter UL-BWP for a cell.

To enable BA on the PCell, a base station may configure a UE with one or more UL and DL BWP pairs. To enable BA on SCells (e.g., in case of CA), a base station may configure a UE at least with one or more DL BWPs (e.g., there may be none in an UL).

In an example, an initial active DL BWP may be defined by at least one of a location and number of contiguous PRBs, a subcarrier spacing, or a cyclic prefix, for a control resource set for at least one common search space. For operation on the PCell, one or more higher layer parameters may indicate at least one initial UL BWP for a random access procedure. If a UE is configured with a secondary carrier on a primary cell, the UE may be configured with an initial BWP for random access procedure on a secondary carrier.

In an example, for unpaired spectrum operation, a UE may expect that a center frequency for a DL BWP may be same as a center frequency for a UL BWP.

For example, for a DL BWP or an UL BWP in a set of one or more DL BWPs or one or more UL BWPs, respectively, a base statin may semi-statistically configure a UE for a cell with one or more parameters indicating at least one of following: a subcarrier spacing; a cyclic prefix; a number of contiguous PRBs; an index in the set of one or more DL BWPs and/or one or more UL BWPs; a link between a DL BWP and an UL BWP from a set of configured DL BWPs and UL BWPs; a DCI detection to a PDSCH reception timing; a PDSCH reception to a HARQ-ACK transmission timing value; a DCI detection to a PUSCH transmission timing value; an offset of a first PRB of a DL bandwidth or an UL bandwidth, respectively, relative to a first PRB of a bandwidth.

In an example, for a DL BWP in a set of one or more DL BWPs on a PCell, a base station may configure a UE with one or more control resource sets for at least one type of common search space and/or one UE-specific search space. For example, a base station may not configure a UE without a common search space on a PCell, or on a PSCell, in an active DL BWP.

For an UL BWP in a set of one or more UL BWPs, a base station may configure a UE with one or more resource sets for one or more PUCCH transmissions.

In an example, if a DCI comprises a BWP indicator field, a BWP indicator field value may indicate an active DL BWP, from a configured DL BWP set, for one or more DL receptions. If a DCI comprises a BWP indicator field, a BWP indicator field value may indicate an active UL BWP, from a configured UL BWP set, for one or more UL transmissions.

In an example, for a PCell, a base station may semi-statistically configure a UE with a default DL BWP among configured DL BWPs. If a UE is not provided a default DL BWP, a default BWP may be an initial active DL BWP.

In an example, a base station may configure a UE with a timer value for a PCell. For example, a UE may start a timer, referred to as BWP inactivity timer, when a UE detects a DCI indicating an active DL BWP, other than a default DL BWP, for a paired spectrum operation or when a UE detects a DCI indicating an active DL BWP or UL BWP, other than a default DL BWP or UL BWP, for an unpaired spectrum operation. The UE may increment the timer by an interval of a first value (e.g., the first value may be 1 millisecond or 0.5 milliseconds) if the UE does not detect a DCI during the interval for a paired spectrum operation or for an unpaired spectrum operation. In an example, the timer may expire when the timer is equal to the timer value. A UE may switch to the default DL BWP from an active DL BWP when the timer expires.

In an example, a base station may semi-statistically configure a UE with one or more BWPs. A UE may switch an active BWP from a first BWP to a second BWP in response to receiving a DCI indicating the second BWP as an active BWP and/or in response to an expiry of BWP inactivity timer (for example, the second BWP may be a default BWP). For example, FIG. 10 is an example diagram of 3 BWPs configured, BWP1 (1010 and 1050), BWP2 (1020 and 1040), and BWP3 (1030). BWP2 (1020 and 1040) may be a default BWP. BWP1 (1010) may be an initial active BWP. In an example, a UE may switch an active BWP from BWP1 1010 to BWP2 1020 in response to an expiry of BWP inactivity timer. For example, a UE may switch an active BWP from BWP2 1020 to BWP3 1030 in response to receiving a DCI indicating BWP3 1030 as an active BWP. Switching an active BWP from BWP3 1030 to BWP2 1040 and/or from BWP2 1040 to BWP1 1050 may be in response to receiving a DCI indicating an active BWP and/or in response to an expiry of BWP inactivity timer.

In an example, if a UE is configured for a secondary cell with a default DL BWP among configured DL BWPs and a timer value, UE procedures on a secondary cell may be same as on a primary cell using the timer value for the secondary cell and the default DL BWP for the secondary cell.

In an example, if a base station configures a UE with a first active DL BWP and a first active UL BWP on a secondary cell or carrier, a UE may employ an indicated DL BWP and an indicated UL BWP on a secondary cell as a respective first active DL BWP and first active UL BWP on a secondary cell or carrier.

FIG. 11A and FIG. 11B show packet flows employing a multi connectivity (e.g. dual connectivity, multi connectivity, tight interworking, and/or the like). FIG. 11A is an example diagram of a protocol structure of a wireless device 110 (e.g. UE) with CA and/or multi connectivity as per an aspect of an embodiment. FIG. 11B is an example diagram of a protocol structure of multiple base stations with CA and/or multi connectivity as per an aspect of an embodiment. The multiple base stations may comprise a master node, MN 1130 (e.g. a master node, a master base station, a master gNB, a master eNB, and/or the like) and a secondary node, SN 1150 (e.g. a secondary node, a secondary base station, a secondary gNB, a secondary eNB, and/or the like). A master node 1130 and a secondary node 1150 may co-work to communicate with a wireless device 110.

When multi connectivity is configured for a wireless device 110, the wireless device 110, which may support multiple reception/transmission functions in an RRC connected state, may be configured to utilize radio resources provided by multiple schedulers of a multiple base stations. Multiple base stations may be inter-connected via a non-ideal or ideal backhaul (e.g. Xn interface, X2 interface, and/or the like). A base station involved in multi connectivity for a certain wireless device may perform at least one of two different roles: a base station may either act as a master base station or as a secondary base station. In multi connectivity, a wireless device may be connected to one master base station and one or more secondary base stations. In an example, a master base station (e.g. the MN 1130) may provide a master cell group (MCG) comprising a primary cell and/or one or more secondary cells for a wireless device (e.g. the wireless device 110). A secondary base station (e.g. the SN 1150) may provide a secondary cell group (SCG) comprising a primary secondary cell (PSCell) and/or one or more secondary cells for a wireless device (e.g. the wireless device 110).

In multi connectivity, a radio protocol architecture that a bearer employs may depend on how a bearer is setup. In an example, three different type of bearer setup options may be supported: an MCG bearer, an SCG bearer, and/or a split bearer. A wireless device may receive/transmit packets of an MCG bearer via one or more cells of the MCG, and/or may receive/transmits packets of an SCG bearer via one or more cells of an SCG. Multi-connectivity may also be described as having at least one bearer configured to use radio resources provided by the secondary base station. Multi-connectivity may or may not be configured/implemented in some of the example embodiments.

In an example, a wireless device (e.g. Wireless Device 110) may transmit and/or receive: packets of an MCG bearer via an SDAP layer (e.g. SDAP 1110), a PDCP layer (e.g. NR PDCP 1111), an RLC layer (e.g. MN RLC 1114), and a MAC layer (e.g. MN MAC 1118); packets of a split bearer via an SDAP layer (e.g. SDAP 1110), a PDCP layer (e.g. NR PDCP 1112), one of a master or secondary RLC layer (e.g. MN RLC 1115, SN RLC 1116), and one of a master or secondary MAC layer (e.g. MN MAC 1118, SN MAC 1119); and/or packets of an SCG bearer via an SDAP layer (e.g. SDAP 1110), a PDCP layer (e.g. NR PDCP 1113), an RLC layer (e.g. SN RLC 1117), and a MAC layer (e.g. MN MAC 1119).

In an example, a master base station (e.g. MN 1130) and/or a secondary base station (e.g. SN 1150) may transmit/receive: packets of an MCG bearer via a master or secondary node SDAP layer (e.g. SDAP 1120, SDAP 1140), a master or secondary node PDCP layer (e.g. NR PDCP 1121, NR PDCP 1142), a master node RLC layer (e.g. MN RLC 1124, MN RLC 1125), and a master node MAC layer (e.g. MN MAC 1128); packets of an SCG bearer via a master or secondary node SDAP layer (e.g. SDAP 1120, SDAP 1140), a master or secondary node PDCP layer (e.g. NR PDCP 1122, NR PDCP 1143), a secondary node RLC layer (e.g. SN RLC 1146, SN RLC 1147), and a secondary node MAC layer (e.g. SN MAC 1148); packets of a split bearer via a master or secondary node SDAP layer (e.g. SDAP 1120, SDAP 1140), a master or secondary node PDCP layer (e.g. NR PDCP 1123, NR PDCP 1141), a master or secondary node RLC layer (e.g. MN RLC 1126, SN RLC 1144, SN RLC 1145, MN RLC 1127), and a master or secondary node MAC layer (e.g. MN MAC 1128, SN MAC 1148).

In multi connectivity, a wireless device may configure multiple MAC entities: one MAC entity (e.g. MN MAC 1118) for a master base station, and other MAC entities (e.g. SN MAC 1119) for a secondary base station. In multi-connectivity, a configured set of serving cells for a wireless device may comprise two subsets: an MCG comprising serving cells of a master base station, and SCGs comprising serving cells of a secondary base station. For an SCG, one or more of following configurations may be applied: at least one cell of an SCG has a configured UL CC and at least one cell of a SCG, named as primary secondary cell (PSCell, PCell of SCG, or sometimes called PCell), is configured with PUCCH resources; when an SCG is configured, there may be at least one SCG bearer or one Split bearer; upon detection of a physical layer problem or a random access problem on a PSCell, or a number of NR RLC retransmissions has been reached associated with the SCG, or upon detection of an access problem on a PSCell during a SCG addition or a SCG change: an RRC connection re-establishment procedure may not be triggered, UL transmissions towards cells of an SCG may be stopped, a master base station may be informed by a wireless device of a SCG failure type, for split bearer, a DL data transfer over a master base station may be maintained; an NR RLC acknowledged mode (AM) bearer may be configured for a split bearer; PCell and/or PSCell may not be de-activated; PSCell may be changed with a SCG change procedure (e.g. with security key change and a RACH procedure); and/or a bearer type change between a split bearer and a SCG bearer or simultaneous configuration of a SCG and a split bearer may or may not supported.

With respect to interaction between a master base station and a secondary base stations for multi-connectivity, one or more of the following may be applied: a master base station and/or a secondary base station may maintain RRM measurement configurations of a wireless device; a master base station may (e.g. based on received measurement reports, traffic conditions, and/or bearer types) may decide to request a secondary base station to provide additional resources (e.g. serving cells) for a wireless device; upon receiving a request from a master base station, a secondary base station may create/modify a container that may result in configuration of additional serving cells for a wireless device (or decide that the secondary base station has no resource available to do so); for a UE capability coordination, a master base station may provide (a part of) an AS configuration and UE capabilities to a secondary base station; a master base station and a secondary base station may exchange information about a UE configuration by employing of RRC containers (inter-node messages) carried via Xn messages; a secondary base station may initiate a reconfiguration of the secondary base station existing serving cells (e.g. PUCCH towards the secondary base station); a secondary base station may decide which cell is a PSCell within a SCG; a master base station may or may not change content of RRC configurations provided by a secondary base station; in case of a SCG addition and/or a SCG SCell addition, a master base station may provide recent (or the latest) measurement results for SCG cell(s); a master base station and secondary base stations may receive information of SFN and/or subframe offset of each other from OAM and/or via an Xn interface, (e.g. for a purpose of DRX alignment and/or identification of a measurement gap). In an example, when adding a new SCG SCell, dedicated RRC signaling may be used for sending required system information of a cell as for CA, except for a SFN acquired from a MIB of a PSCell of a SCG.

FIG. 12 is an example diagram of a random access procedure. One or more events may trigger a random access procedure. For example, one or more events may be at least one of following: initial access from RRC_IDLE, RRC connection re-establishment procedure, handover, DL or UL data arrival during RRC_CONNECTED when UL synchronization status is non-synchronized, transition from RRC_Inactive, and/or request for other system information. For example, a PDCCH order, a MAC entity, and/or a beam failure indication may initiate a random access procedure.

In an example embodiment, a random access procedure may be at least one of a contention based random access procedure and a contention free random access procedure. For example, a contention based random access procedure may comprise, one or more Msg 1 1220 transmissions, one or more Msg2 1230 transmissions, one or more Msg3 1240 transmissions, and contention resolution 1250. For example, a contention free random access procedure may comprise one or more Msg 1 1220 transmissions and one or more Msg2 1230 transmissions.

In an example, a base station may transmit (e.g., unicast, multicast, or broadcast), to a UE, a RACH configuration 1210 via one or more beams. The RACH configuration 1210 may comprise one or more parameters indicating at least one of following: available set of PRACH resources for a transmission of a random access preamble, initial preamble power (e.g., random access preamble initial received target power), an RSRP threshold for a selection of a SS block and corresponding PRACH resource, a power-ramping factor (e.g., random access preamble power ramping step), random access preamble index, a maximum number of preamble transmission, preamble group A and group B, a threshold (e.g., message size) to determine the groups of random access preambles, a set of one or more random access preambles for system information request and corresponding PRACH resource(s), if any, a set of one or more random access preambles for beam failure recovery request and corresponding PRACH resource(s), if any, a time window to monitor RA response(s), a time window to monitor response(s) on beam failure recovery request, and/or a contention resolution timer.

In an example, the Msg1 1220 may be one or more transmissions of a random access preamble. For a contention based random access procedure, a UE may select a SS block with a RSRP above the RSRP threshold. If random access preambles group B exists, a UE may select one or more random access preambles from a group A or a group B depending on a potential Msg3 1240 size. If a random access preambles group B does not exist, a UE may select the one or more random access preambles from a group A. A UE may select a random access preamble index randomly (e.g. with equal probability or a normal distribution) from one or more random access preambles associated with a selected group. If a base station semi-statistically configures a UE with an association between random access preambles and SS blocks, the UE may select a random access preamble index randomly with equal probability from one or more random access preambles associated with a selected SS block and a selected group.

For example, a UE may initiate a contention free random access procedure based on a beam failure indication from a lower layer. For example, a base station may semi-statistically configure a UE with one or more contention free PRACH resources for beam failure recovery request associated with at least one of SS blocks and/or CSI-RSs. If at least one of SS blocks with a RSRP above a first RSRP threshold amongst associated SS blocks or at least one of CSI-RSs with a RSRP above a second RSRP threshold amongst associated CSI-RSs is available, a UE may select a random access preamble index corresponding to a selected SS block or CSI-RS from a set of one or more random access preambles for beam failure recovery request.

For example, a UE may receive, from a base station, a random access preamble index via PDCCH or RRC for a contention free random access procedure. If a base station does not configure a UE with at least one contention free PRACH resource associated with SS blocks or CSI-RS, the UE may select a random access preamble index. If a base station configures a UE with one or more contention free PRACH resources associated with SS blocks and at least one SS block with a RSRP above a first RSRP threshold amongst associated SS blocks is available, the UE may select the at least one SS block and select a random access preamble corresponding to the at least one SS block. If a base station configures a UE with one or more contention free PRACH resources associated with CSI-RSs and at least one CSI-RS with a RSRP above a second RSPR threshold amongst the associated CSI-RSs is available, the UE may select the at least one CSI-RS and select a random access preamble corresponding to the at least one CSI-RS.

A UE may perform one or more Msg1 1220 transmissions by transmitting the selected random access preamble. For example, if a UE selects an SS block and is configured with an association between one or more PRACH occasions and one or more SS blocks, the UE may determine an PRACH occasion from one or more PRACH occasions corresponding to a selected SS block. For example, if a UE selects a CSI-RS and is configured with an association between one or more PRACH occasions and one or more CSI-RSs, the UE may determine a PRACH occasion from one or more PRACH occasions corresponding to a selected CSI-RS. A UE may transmit, to a base station, a selected random access preamble via a selected PRACH occasions. A UE may determine a transmit power for a transmission of a selected random access preamble at least based on an initial preamble power and a power-ramping factor. A UE may determine a RA-RNTI associated with a selected PRACH occasions in which a selected random access preamble is transmitted. For example, a UE may not determine a RA-RNTI for a beam failure recovery request. A UE may determine an RA-RNTI at least based on an index of a first OFDM symbol and an index of a first slot of a selected PRACH occasions, and/or an uplink carrier index for a transmission of Msg1 1220.

In an example, a UE may receive, from a base station, a random access response, Msg 2 1230. A UE may start a time window (e.g., ra-ResponseWindow) to monitor a random access response. For beam failure recovery request, a base station may configure a UE with a different time window (e.g., bfr-ResponseWindow) to monitor response on beam failure recovery request. For example, a UE may start a time window (e.g., ra-ResponseWindow or bfr-ResponseWindow) at a start of a first PDCCH occasion after a fixed duration of one or more symbols from an end of a preamble transmission. If a UE transmits multiple preambles, the UE may start a time window at a start of a first PDCCH occasion after a fixed duration of one or more symbols from an end of a first preamble transmission. A UE may monitor a PDCCH of a cell for at least one random access response identified by a RA-RNTI or for at least one response to beam failure recovery request identified by a C-RNTI while a timer for a time window is running.

In an example, a UE may consider a reception of random access response successful if at least one random access response comprises a random access preamble identifier corresponding to a random access preamble transmitted by the UE. A UE may consider the contention free random access procedure successfully completed if a reception of random access response is successful. If a contention free random access procedure is triggered for a beam failure recovery request, a UE may consider a contention free random access procedure successfully complete if a PDCCH transmission is addressed to a C-RNTI. In an example, if at least one random access response comprises a random access preamble identifier, a UE may consider the random access procedure successfully completed and may indicate a reception of an acknowledgement for a system information request to upper layers. If a UE has signaled multiple preamble transmissions, the UE may stop transmitting remaining preambles (if any) in response to a successful reception of a corresponding random access response.

In an example, a UE may perform one or more Msg 3 1240 transmissions in response to a successful reception of random access response (e.g., for a contention based random access procedure). A UE may adjust an uplink transmission timing based on a timing advanced command indicated by a random access response and may transmit one or more transport blocks based on an uplink grant indicated by a random access response. Subcarrier spacing for PUSCH transmission for Msg3 1240 may be provided by at least one higher layer (e.g. RRC) parameter. A UE may transmit a random access preamble via PRACH and Msg3 1240 via PUSCH on a same cell. A base station may indicate an UL BWP for a PUSCH transmission of Msg3 1240 via system information block. A UE may employ HARQ for a retransmission of Msg 3 1240.

In an example, multiple UEs may perform Msg 1 1220 by transmitting a same preamble to a base station and receive, from the base station, a same random access response comprising an identity (e.g., TC-RNTI). Contention resolution 1250 may ensure that a UE does not incorrectly use an identity of another UE. For example, contention resolution 1250 may be based on C-RNTI on PDCCH or a UE contention resolution identity on DL-SCH. For example, if a base station assigns a C-RNTI to a UE, the UE may perform contention resolution 1250 based on a reception of a PDCCH transmission that is addressed to the C-RNTI. In response to detection of a C-RNTI on a PDCCH, a UE may consider contention resolution 1250 successful and may consider a random access procedure successfully completed. If a UE has no valid C-RNTI, a contention resolution may be addressed by employing a TC-RNTI. For example, if a MAC PDU is successfully decoded and a MAC PDU comprises a UE contention resolution identity MAC CE that matches the CCCH SDU transmitted in Msg3 1250, a UE may consider the contention resolution 1250 successful and may consider the random access procedure successfully completed.

FIG. 13 is an example structure for MAC entities as per an aspect of an embodiment. In an example, a wireless device may be configured to operate in a multi-connectivity mode. A wireless device in RRC_CONNECTED with multiple RX/TX may be configured to utilize radio resources provided by multiple schedulers located in a plurality of base stations. The plurality of base stations may be connected via a non-ideal or ideal backhaul over the Xn interface. In an example, a base station in a plurality of base stations may act as a master base station or as a secondary base station. A wireless device may be connected to one master base station and one or more secondary base stations. A wireless device may be configured with multiple MAC entities, e.g. one MAC entity for master base station, and one or more other MAC entities for secondary base station(s). In an example, a configured set of serving cells for a wireless device may comprise two subsets: an MCG comprising serving cells of a master base station, and one or more SCGs comprising serving cells of a secondary base station(s). FIG. 13 illustrates an example structure for MAC entities when MCG and SCG are configured for a wireless device.

In an example, at least one cell in a SCG may have a configured UL CC, wherein a cell of at least one cell may be called PSCell or PCell of SCG, or sometimes may be simply called PCell. A PSCell may be configured with PUCCH resources. In an example, when a SCG is configured, there may be at least one SCG bearer or one split bearer. In an example, upon detection of a physical layer problem or a random access problem on a PSCell, or upon reaching a number of RLC retransmissions associated with the SCG, or upon detection of an access problem on a PSCell during a SCG addition or a SCG change: an RRC connection re-establishment procedure may not be triggered, UL transmissions towards cells of an SCG may be stopped, a master base station may be informed by a UE of a SCG failure type and DL data transfer over a master base station may be maintained.

In an example, a MAC sublayer may provide services such as data transfer and radio resource allocation to upper layers (e.g. 1310 or 1320). A MAC sublayer may comprise a plurality of MAC entities (e.g. 1350 and 1360). A MAC sublayer may provide data transfer services on logical channels. To accommodate different kinds of data transfer services, multiple types of logical channels may be defined. A logical channel may support transfer of a particular type of information. A logical channel type may be defined by what type of information (e.g., control or data) is transferred. For example, BCCH, PCCH, CCCH and DCCH may be control channels and DTCH may be a traffic channel. In an example, a first MAC entity (e.g. 1310) may provide services on PCCH, BCCH, CCCH, DCCH, DTCH and MAC control elements. In an example, a second MAC entity (e.g. 1320) may provide services on BCCH, DCCH, DTCH and MAC control elements.

A MAC sublayer may expect from a physical layer (e.g. 1330 or 1340) services such as data transfer services, signaling of HARQ feedback, signaling of scheduling request or measurements (e.g. CQI). In an example, in dual connectivity, two MAC entities may be configured for a wireless device: one for MCG and one for SCG. A MAC entity of wireless device may handle a plurality of transport channels. In an example, a first MAC entity may handle first transport channels comprising a PCCH of MCG, a first BCH of MCG, one or more first DL-SCHs of MCG, one or more first UL-SCHs of MCG and one or more first RACHs of MCG. In an example, a second MAC entity may handle second transport channels comprising a second BCH of SCG, one or more second DL-SCHs of SCG, one or more second UL-SCHs of SCG and one or more second RACHs of SCG.

In an example, if a MAC entity is configured with one or more SCells, there may be multiple DL-SCHs and there may be multiple UL-SCHs as well as multiple RACHs per MAC entity. In an example, there may be one DL-SCH and UL-SCH on a SpCell. In an example, there may be one DL-SCH, zero or one UL-SCH and zero or one RACH for an SCell. A DL-SCH may support receptions using different numerologies and/or TTI duration within a MAC entity. A UL-SCH may also support transmissions using different numerologies and/or TTI duration within the MAC entity.

In an example, a MAC sublayer may support different functions and may control these functions with a control (e.g. 1355 or 1365) element. Functions performed by a MAC entity may comprise mapping between logical channels and transport channels (e.g., in uplink or downlink), multiplexing (e.g. 1352 or 1362) of MAC SDUs from one or different logical channels onto transport blocks (TB) to be delivered to the physical layer on transport channels (e.g., in uplink), demultiplexing (e.g. 1352 or 1362) of MAC SDUs to one or different logical channels from transport blocks (TB) delivered from the physical layer on transport channels (e.g., in downlink), scheduling information reporting (e.g., in uplink), error correction through HARQ in uplink or downlink (e.g. 1363), and logical channel prioritization in uplink (e.g. 1351 or 1361). A MAC entity may handle a random access process (e.g. 1354 or 1364).

FIG. 14 is an example diagram of a RAN architecture comprising one or more base stations. In an example, a protocol stack (e.g. RRC, SDAP, PDCP, RLC, MAC, and PHY) may be supported at a node. A base station (e.g. 120A or 120B) may comprise a base station central unit (CU) (e.g. gNB-CU 1420A or 1420B) and at least one base station distributed unit (DU) (e.g. gNB-DU 1430A, 1430B, 1430C, or 1430D) if a functional split is configured. Upper protocol layers of a base station may be located in a base station CU, and lower layers of the base station may be located in the base station DUs. An F1 interface (e.g. CU-DU interface) connecting a base station CU and base station DUs may be an ideal or non-ideal backhaul. F1-C may provide a control plane connection over an F1 interface, and F1-U may provide a user plane connection over the F1 interface. In an example, an Xn interface may be configured between base station CUs.

In an example, a base station CU may comprise an RRC function, an SDAP layer, and a PDCP layer, and base station DUs may comprise an RLC layer, a MAC layer, and a PHY layer. In an example, various functional split options between a base station CU and base station DUs may be possible by locating different combinations of upper protocol layers (RAN functions) in a base station CU and different combinations of lower protocol layers (RAN functions) in base station DUs. A functional split may support flexibility to move protocol layers between a base station CU and base station DUs depending on service requirements and/or network environments.

In an example, functional split options may be configured per base station, per base station CU, per base station DU, per UE, per bearer, per slice, or with other granularities. In per base station CU split, a base station CU may have a fixed split option, and base station DUs may be configured to match a split option of a base station CU. In per base station DU split, a base station DU may be configured with a different split option, and a base station CU may provide different split options for different base station DUs. In per UE split, a base station (base station CU and at least one base station DUs) may provide different split options for different wireless devices. In per bearer split, different split options may be utilized for different bearers. In per slice splice, different split options may be applied for different slices.

FIG. 15 is an example diagram showing RRC state transitions of a wireless device. In an example, a wireless device may be in at least one RRC state among an RRC connected state (e.g. RRC Connected 1530, RRC_Connected), an RRC idle state (e.g. RRC Idle 1510, RRC_Idle), and/or an RRC inactive state (e.g. RRC Inactive 1520, RRC_Inactive). In an example, in an RRC connected state, a wireless device may have at least one RRC connection with at least one base station (e.g. gNB and/or eNB), which may have a UE context of the wireless device. A UE context (e.g. a wireless device context) may comprise at least one of an access stratum context, one or more radio link configuration parameters, bearer (e.g. data radio bearer (DRB), signaling radio bearer (SRB), logical channel, QoS flow, PDU session, and/or the like) configuration information, security information, PHY/MAC/RLC/PDCP/SDAP layer configuration information, and/or the like configuration information for a wireless device. In an example, in an RRC idle state, a wireless device may not have an RRC connection with a base station, and a UE context of a wireless device may not be stored in a base station. In an example, in an RRC inactive state, a wireless device may not have an RRC connection with a base station. A UE context of a wireless device may be stored in a base station, which may be called as an anchor base station (e.g. last serving base station).

In an example, a wireless device may transition a UE RRC state between an RRC idle state and an RRC connected state in both ways (e.g. connection release 1540 or connection establishment 1550; or connection reestablishment) and/or between an RRC inactive state and an RRC connected state in both ways (e.g. connection inactivation 1570 or connection resume 1580). In an example, a wireless device may transition its RRC state from an RRC inactive state to an RRC idle state (e.g. connection release 1560).

In an example, an anchor base station may be a base station that may keep a UE context (a wireless device context) of a wireless device at least during a time period that a wireless device stays in a RAN notification area (RNA) of an anchor base station, and/or that a wireless device stays in an RRC inactive state. In an example, an anchor base station may be a base station that a wireless device in an RRC inactive state was lastly connected to in a latest RRC connected state or that a wireless device lastly performed an RNA update procedure in. In an example, an RNA may comprise one or more cells operated by one or more base stations. In an example, a base station may belong to one or more RNAs. In an example, a cell may belong to one or more RNAs.

In an example, a wireless device may transition a UE RRC state from an RRC connected state to an RRC inactive state in a base station. A wireless device may receive RNA information from the base station. RNA information may comprise at least one of an RNA identifier, one or more cell identifiers of one or more cells of an RNA, a base station identifier, an IP address of the base station, an AS context identifier of the wireless device, a resume identifier, and/or the like.

In an example, an anchor base station may broadcast a message (e.g. RAN paging message) to base stations of an RNA to reach to a wireless device in an RRC inactive state, and/or the base stations receiving the message from the anchor base station may broadcast and/or multicast another message (e.g. paging message) to wireless devices in their coverage area, cell coverage area, and/or beam coverage area associated with the RNA through an air interface.

In an example, when a wireless device in an RRC inactive state moves into a new RNA, the wireless device may perform an RNA update (RNAU) procedure, which may comprise a random access procedure by the wireless device and/or a UE context retrieve procedure. A UE context retrieve may comprise: receiving, by a base station from a wireless device, a random access preamble; and fetching, by a base station, a UE context of the wireless device from an old anchor base station. Fetching may comprise: sending a retrieve UE context request message comprising a resume identifier to the old anchor base station and receiving a retrieve UE context response message comprising the UE context of the wireless device from the old anchor base station.

In an example embodiment, a wireless device in an RRC inactive state may select a cell to camp on based on at least a on measurement results for one or more cells, a cell where a wireless device may monitor an RNA paging message and/or a core network paging message from a base station. In an example, a wireless device in an RRC inactive state may select a cell to perform a random access procedure to resume an RRC connection and/or to transmit one or more packets to a base station (e.g. to a network). In an example, if a cell selected belongs to a different RNA from an RNA for a wireless device in an RRC inactive state, the wireless device may initiate a random access procedure to perform an RNA update procedure. In an example, if a wireless device in an RRC inactive state has one or more packets, in a buffer, to transmit to a network, the wireless device may initiate a random access procedure to transmit one or more packets to a base station of a cell that the wireless device selects. A random access procedure may be performed with two messages (e.g. 2 stage random access) and/or four messages (e.g. 4 stage random access) between the wireless device and the base station.

In an example embodiment, a base station receiving one or more uplink packets from a wireless device in an RRC inactive state may fetch a UE context of a wireless device by transmitting a retrieve UE context request message for the wireless device to an anchor base station of the wireless device based on at least one of an AS context identifier, an RNA identifier, a base station identifier, a resume identifier, and/or a cell identifier received from the wireless device. In response to fetching a UE context, a base station may transmit a path switch request for a wireless device to a core network entity (e.g. AMF, MME, and/or the like). A core network entity may update a downlink tunnel endpoint identifier for one or more bearers established for the wireless device between a user plane core network entity (e.g. UPF, S-GW, and/or the like) and a RAN node (e.g. the base station), e.g. changing a downlink tunnel endpoint identifier from an address of the anchor base station to an address of the base station.

In existing technologies, an IAB-donor has an RRC function to serve a wireless device. A wireless device may experience an RRC connection failure when a backhaul link failure between a serving IAB-node and a serving IAB-donor occurs. In an implementation of existing technologies, when receiving a wireless device report of an RRC connection failure that is due to a backhaul link failure, a base station may misinterpret an RRC connection failure as an access link issue between a wireless device and an IAB-node. An implementation of existing technologies may increase improper radio parameter configurations when an IAB-node backhaul link is failed. Existing technologies may decrease radio access reliability of wireless devices.

Example embodiments supports a radio link failure report mechanism providing backhaul link information of wireless devices. Example embodiment may support radio communication parameters to be configured based on status information of a radio backhaul link. Implementation of example embodiments may increase communication reliability and mobility performance of wireless devices.

In an example, an IAB-node may be interpreted as at least one of an intermediate network node, an IAB-donor, a base station, a gNB, a gNB-DU, an eNB, a relay node, a wireless device, a UE, an access point, and/or the like. In an example, an IAB-donor may be interpreted as at least one of a base station, a gNB, a gNB-CU, an eNB, a relay donor node, IAB-node, an access point and/or the like. In an example, a wireless device may be interpreted as a user equipment (UE), an IAB-node, an IAB-donor, a relay node, a base station, a gNB, and/or the like.

In an example, an integrated access and backhaul (IAB) may support a wireless backhaul connection for an access network node (e.g. distributed unit, gNB-DU, base station, gNB, IAB-node, relay node, mobile relay node, RAN node, and/or the like). In an example, an IAB-node may indicate a RAN node that may support wireless access to UEs and/or wirelessly backhauls access traffic. In an example, an IAB-donor may indicate a RAN node which may provide UE's interface to core network and/or wireless backhauling functionality to IAB nodes.

In an example, IAB may enable flexible and/or very dense deployment of cells without densifying the transport network proportionately. A diverse range of deployment scenarios may be envisioned including support for outdoor small cell deployments, indoors, and/or even mobile relays (e.g. on buses and/or trains). IAB may support physically fixed relays and/or mobile relays.

In example IAB deployment, in-band and/or out-of-band backhauling with respect to the access link may be supported. In-band backhauling may include scenarios, where access and backhaul link at least partially overlap in frequency creating half-duplexing or interference constraints. Half-duplexing constraint and/or interference constraints of in-band backhauling may imply that IAB node may not transmit and receive simultaneously on both links. In an example, out-of-band scenarios may not pose half-duplexing constraint and/or interference constraints. In in-band backhauling deployments, tighter interworking between access and backhaul in compliance with half-duplexing and interference constraints may be needed.

In an example, in-band IAB scenarios may support TDM/FDM/SDM of access and backhaul links subject to half-duplex constraint at the IAB node. In an example, in-band IAB scenario may support full duplex solutions. In an example, out-of-band IAB scenarios may be supported using the same set of RAN features designed for in-band scenarios.

In an example, IAB may support access and backhaul in above-6 GHz- and/or sub-6 GHz spectrum. Backhauling of access traffic over the same RAT backhaul links may be supported. Inter-RAT operation for backhauling and access may be supported.

UEs may transparently connect to an IAB-node via the same RAT. IAB architectures required for a first RAT access over a second RAT backhaul may be supported

In an example, IAB may support stand-alone (SA) and/or non-stand-alone (NSA) deployments. For NSA, IAB-based relaying of UE's secondary cell group (SCG) path may be supported. IAB-based relaying of UE's master cell group (MCG) path be supported.

An IAB node may operate in SA and/or NSA mode. In an example, EN-DC and SA option 2 may be supported. In an example, EN-DC and SA option 2 for UEs and IAB-nodes may be supported. NSA deployment options and/or combinations of SA and NSA may be supported.

In an example, SA and/or NSA may be supported for access link. For an NSA access link, relaying may be applied to RAN node. In an example, both NSA and SA may be supported for backhaul link. Backhaul traffic over radio interface may be supported. In an example, for NSA access and backhaul links, EN-DC may be supported.

In an example, multi-hop backhauling may provide more range extension than single hop. Multi-hop backhauling may be beneficial for above-6 GHz frequencies due to their limited range. Multi-hop backhauling may enable backhauling around obstacles, e.g. buildings in urban environment for in-clutter deployments. In an example, the number of hops in IAB deployment may be expected to depend on many factors such as frequency, cell density, propagation environment, and/or traffic load. These factors may be expected to change over time. From the architecture perspective, flexibility in hop count may be desirable.

In an example, with increasing number of hops, scalability issues may limit performance and/or increase signaling load. Capturing scalability to hop count may affect system performances. IAB design may support multiple backhaul hops. In an example, IAB architecture may not limit on the number of backhaul hops. Scalability to hop-count may be supported. In an example, single hop may be considered (e.g. interpreted as) a special case of multiple backhaul hops.

In an example, wireless backhaul links may be vulnerable to blockage, e.g., due to moving objects such as vehicles, due to seasonal changes (foliage), and/or due to infrastructure changes (e.g. new buildings). Vulnerability of wireless backhaul links may apply to physically stationary IAB-nodes. In an example, traffic variations may create uneven load distribution on wireless backhaul links leading to local link and/or node congestion.

In an example, topology adaptation (e.g. adaptive routing) may refer to procedures that autonomously reconfigure backhaul network under circumstances such as blockage and/or local congestion without discontinuing services for UEs. In an example, topology adaptation for physically fixed relays may be supported to enable robust operation, e.g., mitigate blockage and/or load variation on backhaul links.

In an example, for IAB implementation, layer 2 (L2) and layer 3 (L3) relay architectures may be supported.

In an example, IAB-related features such as IAB-node integration and/or topology adaptation may affect core network operations. In an example, IAB features may create additional core-network signaling load. An amount of signaling load of core network nodes may vary among the various designs of IAB architectures.

In an example, time synchronization between IAB nodes may be implemented e.g. to support TDD system and/or some potential features which may need network synchronization. IAB may support additional implementations on network synchronization, which may include in-band wireless backhaul and/or multi-hops backhauling.

In an example, IAB architectures may comprise mobile-termination (MT), gNB-DU, gNB-CU, UPF, AMF and SMF as well as the corresponding interfaces NR Uu (between MT and gNB), F1, NG, X2 and N4. IAB architecture may be configured based on modifications or enhancements to these functions and interfaces. An mobile-termination (MT) function may be defined a component of a mobile equipment (e.g. user equipment, UE). In an example, MT may be referred to as a function residing on an IAB-node that terminates radio interface layers of a backhaul Uu interface toward an IAB-donor and/or other IAB-nodes.

FIG. 16 shows an example diagram for IAB in standalone mode, which may contain one IAB-donor and multiple IAB-nodes. An IAB-donor may be treated as a single logical node that may comprise a set of functions such as gNB-DU, gNB-CU-CP, gNB-CU-UP and/or potentially other functions. In a deployment, an IAB-donor may be split according to these functions, which may be collocated and/or non-collocated. IAB architectures may operate with split of these functions. In an example, some of functions associated with an IAB-donor may be moved outside of the donor in some cases.

In an example, an IAB node may operate in SA mode and/or in NSA mode. When operating in NSA, an IAB-node may use other link for backhauling. In an example, a UE connecting to an IAB-node may choose a different operation mode than the IAB-node. A UE may connect to a different type of core network than an IAB-node that the UE is connected to. In this case, (e)Decor or slicing may be used for core network selection. IAB-nodes operating in NSA-mode may be connected to the same or to different base stations (e.g. gNBs, eNBs). UEs that operate in NSA-node may connect to the same or to a different base stations than an IAB-node that they are connected to. FIG. 17 shows examples for SA-mode and NSA-mode with core network(s).

In an example, IAB multi-hop designs may differ with respect to modification needed on interfaces and/or additional functionality needed, e.g. to accomplish multi-hop forwarding. Example architectures may be divided into two architecture groups.

In an example, architecture group 1 may comprise architectures 1a and/or 1b. The architecture 1a and/or 1b may leverage CU/DU split architecture. Architecture 1a may comprise backhauling of F1-U using an adaptation layer and/or GTP-U combined with an adaptation layer. Architecture 1a may employ hop-by-hop forwarding across intermediate nodes using an adaptation layer for operation with core network and/or PDN-connection-layer routing for operation with other core networks (e.g. other RAT, EPC). In an example, architecture 1b may comprise backhauling of F1-U on access node using GTP-U/UDP/IP. Architecture 1b may employ hob-by-hop forwarding across intermediate node using an adaptation layer.

In an example, architecture group 2 may comprise architectures 2a, 2b, and/or 2c. Architecture 2a may comprise backhauling of F1-U or NG-U on access node using GTP-U/UDP/IP. Architecture 2a may employ hop-by-hop forwarding across intermediate node using PDU-session-layer routing. Architecture 2b may comprise backhauling of F1-U or NG-U on access node using GTP-U/UDP/IP. Architecture 2b may employ hop-by-hop forwarding across intermediate node using GTP-U/UDP/IP nested tunneling. Architecture 2c may comprise backhauling of F1-U or NG-U on access node using GTP-U/UDP/IP. Architecture 2c may employ hop-by-hop forwarding across intermediate node using GTP-U/UDP/IP/PDCP nested tunneling.

In an example, architecture 1a may leverage CU/DU-split architecture. FIG. 18 shows an example diagram for a two-hop chain of IAB-nodes underneath an IAB-donor, where IAB-node and UE connect in SA-mode to a core network node (e.g. AMF, UPF, SMF, MME, SGW). In an architecture 1a, an IAB node may hold a DU and/or an MT. Via an MT, an IAB-node may connect to an upstream IAB-node and/or an IAB-donor. Via a DU, an IAB-node may establish RLC-channels to UEs and/or to MTs of downstream IAB-nodes. For MTs, an RLC-channel may refer to a modified RLC*. An IAB node may connect to more than one upstream IAB-node and/or IAB-donor.

In an example of an architecture 1a, a donor (IAB-donor) may hold a DU to support UEs and/or MTs of downstream IAB-nodes. An IAB-donor may hold a CU for DUs of IAB-nodes and/or for its own DU. Different CUs may serve DUs of IAB-nodes. A DU on an IAB-node may connect to a CU in an IAB-donor using a modified form of F1, which is referred to as F1*. F1*-U may run over RLC channels on a wireless backhaul between an MT on a serving IAB-node and a DU on a donor. F1*-U transport between MT and DU on a serving IAB-node and/or between DU and CU on a donor may be configured. In an example, an adaptation layer may be added, which may hold routing information, enabling hop-by-hop forwarding. An adaptation layer may replace an IP functionality of an F1-stack. F1*-U may carry a GTP-U header for end-to-end association between CU and DU. In an example, information carried via GTP-U header may be included into an adaption layer.

In an example of an architecture 1a, an RLC may apply ARQ on an end-to-end connection and/or hop-by-hop. FIG. 18 shows examples of F1*-U protocol stacks. RLC* may refer to enhancements of RLC. An MT of IAB-node may sustain NAS connectivity to a core network node (e.g. AMF, SMF, MME, and/or the like core node), e.g., for authentication of an IAB-node. An MT of IAB-node may sustain a PDU session via a core network node (e.g. UPF, SGW, PGW, and/or the like core node), e.g., to provide an IAB-node with connectivity to an operation and management (OAM). In an example, for NSA operation with core network, an MT may be dual-connected with networks (e.g. gNB, eNB, RNC, core network). IAB-node's MT may sustain a PDN connection with core network, e.g., to provide an IAB-node with connectivity to an OAM. Protocol translation between F1* and F1 in case that an IAB-donor is split may be supported.

In an example, architecture 1b may leverage CU/DU-split architecture. FIG. 19 shows an example diagram for a two-hop chain of IAB-nodes underneath an IAB-donor. An IAB-donor may hold one logical CU. An IAB node may connect to more than one upstream IAB-node and/or IAB-donor. In an example of architecture 1b, an IAB-node and/or an IAB-donor may hold the same functions as in architecture 1a. In an example, as in architecture 1a, a backhaul link may establish an RLC-channel. In architecture 1b, an adaptation layer may be inserted to enable hop-by-hop forwarding of F1*.

In an example of architecture 1b, an MT on an IAB-node may establishes a PDU session with a UPF residing on a donor (IAB-donor). MT's PDU session may carry F1* for a collocated DU. In an example, a PDU session may provide a point-to-point link between CU and DU. On intermediate hops, PDCP-PDUs of F1* may be forwarded via adaptation layer. FIG. 19 shows an example of an F1*-U protocol stack. For NSA operation with core network, an MT may be dual-connected with networks (e.g. gNB, eNB, RNC, core network). IAB-node's MT may sustain a PDN connection with a local gateway (L-GW) residing on the donor.

FIG. 20 shows an example diagram for architecture 2a, where UE and/or IAB-node may use SA-mode with core network. In an example, of architecture 2a, an IAB-node may hold an MT to establish a Uu link with a gNB (base station) on a parent IAB-node and/or IAB-donor. Via a Uu link, an MT may sustain a PDU session with a UPF that may by collocated with a gNB. An independent PDU session may be created on a backhaul link (e.g. hop-by-hop). An IAB-node may support a routing function to forward data between PDU sessions of adjacent links. A routing function may create a forwarding plane across a wireless backhaul. Based on PDU session type, a forwarding plane may support IP and/or Ethernet. In case that PDU-session type is Ethernet, an IP layer may be established on top. An IAB-node may obtain IP connectivity to a wireline backhaul network. An IAB node may connect to more than one upstream IAB-node and/or IAB-donor.

In an example of architecture 2a, IP-based interfaces (e.g. NG, Xn, F1, N4, etc.) may be carried over a forwarding plane. In case of F1, a UE-serving IAB-node may contain a DU for access links in addition to a gNB and/or UPF for backhaul links. A CU for access links may reside in or beyond an IAB Donor. FIG. 20 shows an example of an NG-U protocol stack for IP-based and/or for Ethernet-based PDU-session type. In case that an IAB-node holds a DU for UE-access, PDCP-based protection on a hop may not be required since end user data may be protected using end to end PDCP between a UE and a CU. For NSA operation with core network, an MT may be dual-connected with networks (e.g. gNB, eNB, RNC, core network). IAB-node's MT may sustain a PDN-connection with a L-GW residing on a parent IAB-node and/or an IAB-donor. IP-based interfaces (e.g. NG, Xn, S1, S5, X2, etc.) may be carried over a forwarding plane.

In an example of architecture 2b, as shown in FIG. 21, an IAB-node may hold an MT to establish a Uu link with a gNB (base station) on a parent IAB-node and/or IAB-donor. Via a Uu link, an MT may sustain a PDU session with a UPF. A UPF may be located at an IAB-donor. Forwarding of PDUs across upstream IAB-nodes may be accomplished via tunneling. Forwarding across multiple hops may create a stack of nested tunnels. An IAB-node may obtain IP-connectivity to a wireline backhaul network. IP-based interfaces (e.g. NG, Xn, F1, N4, etc.) may be carried over a forwarding IP plane. FIG. 21 shows a protocol stack example for NG-U (e.g. S1-U). An IAB node may connect to more than one upstream IAB-node and/or IAB-donor. For NSA operation with core network, an MT may be dual-connected with networks (e.g. gNB, eNB, RNC, core network). IAB-node's MT may sustain a PDN-connection with a L-GW residing on an IAB-donor.

In an example, as shown in FIG. 22, architecture 2c may leverage DU-CU split. An IAB-node may hold an MT which may sustain an RLC-channel with a DU on a parent IAB-node and/or IAB-donor. An IAB donor may hold a CU and/or a UPF for IAB-node's DU. An MT on an IAB-node may sustain a Uu link with a CU and/or a PDU session with a UPF on a donor (IAB-donor). Forwarding on intermediate nodes may be accomplished via tunneling. Forwarding across multiple hops may create a stack of nested tunnels. An IAB-node may obtain IP-connectivity to wireline backhaul network. A tunnel may include an SDAP/PDCP layer. IP-based interfaces (e.g. NG, Xn, F1, N4, etc.) may be carried over a forwarding plane. FIG. 22 shows a protocol stack example for NG-U (e.g. S1-U). An IAB node may connect to more than one upstream IAB-node and/or IAB-donor. For NSA operation with core network, an MT may be dual-connected with networks (e.g. gNB, eNB, RNC, core network). IAB-node's MT may sustain a PDN-connection with a L-GW residing on an IAB-donor.

In an example, an IAB node may follow the same initial access procedure as an UE (e.g. wireless device), comprising cell search, system information (SI) acquisition, and/or random access, to initially set up a connection to a parent IAB-node and/or a IAB-donor. An SSB/CSI-RS based RRM measurement may be supported for IAB-node discovery and/or measurement. In an example, an inter IAB-node discovery procedure subject to half-duplex constraint and/or multi-hop topologies may be supported, including how to avoid conflicting SSB configurations among IAB-nodes and/or feasibility of CSI-RS based IAB-node discovery. When considering a cell ID used by a given IAB-node, IAB-donor and IAB-node may share the same cell ID, and/or IAB-donor and IAB-node may maintain separate cell IDs. Feasibility of sharing the same cell ID by IAB-donor and IAB-node may depend on IAB architectures. Mechanisms for multiplexing of RACH transmissions from UEs and RACH transmissions from IAB-nodes may be supported.

In an example, measurements on multiple backhaul links for link management and/or route selection may be supported. To support a half-duplex constraint in an IAB-node, IAB may support detection and/or measurement of candidate backhaul links (e.g. after initial access), which may utilize resources that may be orthogonal in time from those used by access UEs for cell detection and/or measurement. To support measurement, IAB may support at least one of: TDM of SSBs (e.g. depending on hop order, cell ID, etc.); SSB muting across IAB-nodes; multiplexing of SSBs for access UEs and IABs within a half-frame and/or across half-frames; additional IAB-node discovery signal which may be TDM with SSB transmissions (e.g. CSI-RS), use of off-raster SSBs; different transmission periodicity for backhaul link detection and/or measurement compared to the periodicity used by access UEs; and/or the like. Coordination mechanisms for different solutions may be supported, including mechanisms for coordination of reference signal (RS) transmission and/or measurement occasions for IAB-nodes. Enhancements of SMTC and/or CSI-RS configurations to support RRM measurement for IAB-nodes may be considered.

In an example, an IAB-node may support mechanisms for detecting/recovering from backhaul link failure. Enhancements to RLM RS and/or associated procedures for IAB may be supported.

In an example, mechanisms for route switching and/or transmission/reception on multiple backhaul links simultaneously (e.g. multi-TRP operation and/or intra-frequency dual connectivity) may be supported. Feasibility of those mechanisms may depend on IAB architectures.

In an example, downlink IAB node transmissions (e.g. transmissions on backhaul links from an IAB-node to child IAB-nodes served by the IAB-node and transmissions on access links from an IAB-node to UEs served by the IAB-node) may be scheduled by an IAB-node. In an example, uplink IAB transmission (e.g. transmissions on a backhaul link from an IAB-node to its parent IAB-node and/or IAB-donor) may be scheduled by a parent IAB-node or an IAB-donor.

In an example, IAB may support time division multiplexing (TDM), frequency division multiplexing (FDM), and/or space division multiplexing (SDM) between access and backhaul links at an IAB-node, e.g. subject to a half-duplex constraint. Mechanisms for TDM/FDM/SDM multiplexing of access/backhaul traffic across multiple hops may consider an IAB node half-duplex constraint. In an example, IAB may support mechanisms for orthogonal partitioning of time slots and/or frequency resources between access and backhaul links across one or multiple hops. IAB may provide utilization of different DL/UL slot configurations for access and backhaul links. IAB may support DL and/or UL power control enhancements and/or timing requirements to allow for intra-panel FDM and/or SDM of backhaul and access links. In an example, IAB may provide interference management including cross-link interference.

In an example, IAB may provide mechanisms for scheduling coordination, resource allocation, and/or route selection across IAB-nodes/IAB-donors and/or multiple backhaul hops. Semi-static (e.g. on the timescale of RRC signaling) may be supported for resource (e.g. frequency, time in terms of slot/slot format, etc.) coordination between IAB-nodes. In an example, IAB may support distributed and/or centralized resource coordination mechanisms. IAB may support various resource granularity of required signaling (e.g. TDD configuration pattern). IAB-nodes and/or IAB-donors may exchange information of L1 and/or L3 measurements. In an example, IAB-nodes and/or IAB-donors may exchange topology related information (e.g. hop order) based on the backhaul link physical layer design. IAB may support may support resource (e.g. frequency, time in terms of slot/slot format, etc.) coordination which may be faster than semi-static coordination.

In an example, over-the-air (OTA) synchronization may be configured for IAB. In an example, IAB may support mechanism to adjust timing alignment of IAB-nodes. IAB may support detection and management of timing misalignment (e.g. depending on the number of hops). In an example, IAB may implement mechanisms for timing alignment across multi-hop IAB networks. IAB may support TA-based synchronization between IAB-nodes, including across multiple backhaul hops. In an example, IAB may support various cases of transmission timing alignment across IAB-nodes and/or IAB-donors: DL transmission timing alignment across IAB-nodes and/or IAB-donors; DL and UL transmission timing aligned within an IAB-node; DL and UL reception timing aligned within an IAB-node; timing alignment within an IAB-node when transmitting DL and UL and receiving DL and UL; DL transmission timing alignment across IAB-nodes and/or IAB-donors for access link; and/or timing alignment within an IAB-node when transmitting DL and UL and receiving DL and UL for backhaul link timing in different time slots.

In an example, levels of timing alignment between IAB-nodes/IAB-donors and/or within an IAB-node may comprise slot-level alignment, symbol-level alignment, and/or no alignment. IAB implementation for TDM/FDM/SDM multiplexing of access and backhaul links, cross-link interference, and/or access UEs may be supported.

In an example, IAB may control cross-link interference (CLI) on access and backhaul links (including across multiple hops) by providing interference measurement and management mechanisms.

In an example, IAB CLI mitigation techniques may support advanced receivers and transmitter coordination. CLI mitigation techniques may support interference mitigation mechanisms for inter IAB-node interference scenarios, for example: victim IAB-node is receiving in DL via its MT, interfering IAB-node is transmitting in UL via its MT; victim IAB-node is receiving in DL via its MT, interfering IAB-node is transmitting in DL via its DU; victim IAB-node is receiving in UL via its DU, interfering IAB-node is transmitting in UL via its MT; and/or victim IAB-node is receiving in UL via its DU, interfering IAB-node is transmitting in DL via its DU. IAB may implement mechanisms to resolve interference experienced at the IAB-node in case of FDM/SDM reception between access and backhaul links at an IAB-node. In an example, IAB may support CLI measurements, e.g. short-term/long term measurements, and/or multiple-antenna and beamforming based measurements, and may support CLI mitigation in IAB-nodes and/or IAB-donors.

IAB may support wireless backhaul links with high spectral efficiency. In an example, IAB may support 1024QAM for the backhaul link.

In an example, UE may establish RLC channels to a DU on UE's access IAB node. RLC-channels may be extended via a modified form of F1-U, referred to as F1*-U, between UE's access DU and an IAB donor. Information embedded in F1*-U may be carried over RLC-channels across backhaul links. Transport of F1*-U over a wireless backhaul may be enabled by an adaptation layer, which may be integrated with the RLC channel. An IAB-donor (referred to as fronthaul) may use F1-U stack. An IAB-donor DU may relay between F1-U on a fronthaul and/or F1*-U on a wireless backhaul.

In an example of architecture 1a, information carried on an adaptation layer may support one or more functions of: identification of a UE-bearer for the PDU, routing across a wireless backhaul topology, QoS-enforcement by a scheduler on DL and UL on a wireless backhaul link, mapping of UE user-plane PDUs to backhaul RLC channels, and/or the like.

In an example of architecture 1b, information carried on the adaptation layer may support one or more functions of: routing across a wireless backhaul topology, QoS-enforcement by a scheduler on DL and UL on a wireless backhaul link, mapping of UE user-plane PDUs to backhaul RLC channels, and/or the like.

In an example, information to be carried on an adaptation layer header may comprise one or more of: UE-bearer-specific Id, UE-specific Id, Route Id, IAB-node, IAB-donor address, QoS information, and/or the like.

In an example, information on an adaptation layer may be processed to support adaptation layer functions on an on-path IAB-node (e.g. hop-by-hop) and/or on UE's access-IAB-node and an IAB-donor (e.g. end-to-end).

In an example, an adaptation layer may be integrated with MAC layer or above MAC layer, as shown in FIG. 23 (e.g. a, b). In an example, an adaptation layer may be integrated with above RLC layer, as shown in FIG. 23 (e.g. c, d, e) and/or FIG. 24.

In an example, FIG. 23 and/or FIG. 24 show example protocol stacks. While RLC channels serving for backhauling include an adaptation layer, an adaptation layer may be included in IAB-node access links.

In an example, an adaptation layer may comprise sublayers. A GTP-U header may become a part of an adaptation layer. In an example, a GTP-U header may be carried on top of an adaptation layer to carry end-to-end association between an IAB-node DU and a CU (e.g. as shown in FIG. 23 d).

In an example, an IP header may be part of an adaptation layer and/or carried on top of an adaptation layer (e.g. as shown in FIG. 23 e). In an example, an IAB-donor DU may hold an IP routing function to extend an IP-routing plane of a fronthaul to an IP-layer carried by adapt on a wireless backhaul. This may allow native F1-U to be established end-to-end, e.g. between IAB-node DUs and IAB-donor CU-UP. An IAB-node may hold an IP-address, which may be routable from a fronthaul via an IAB-donor DU. IAB-nodes' IP addresses may be used for routing on a wireless backhaul. An IP-layer on top of adapt may not represent a PDU session. MT's first hop router on an IP-layer may not hold a UPF.

In an example, an above-RLC adaptation layer may support hop-by-hop ARQ. An above-MAC adaptation layer may support both hop-by-hop and end-to-end ARQ. In an example, both adaptation layer placements may support aggregated routing, e.g. by inserting an IAB-node address into an adaptation header. In an example, both adaptation layer placements may support per-UE-bearer QoS for a large number of UE-bearers. In an example, for above-RLC adaptation layer, an LCID space may be enhanced since a UE-bearer may be mapped to an independent logical channel. In an example, for above-MAC adaptation layer, UE-bearer-related info may be carried on an adaptation header. In an example, both adaptation layer placements may support aggregated QoS handling e.g. by inserting an aggregated QoS Id into an adaptation header. In an example, aggregated QoS handling may reduce the number of queues. An aggregated QoS handling may be independent on where an adaptation layer is placed. In an example, for both adaptation layer placements, aggregation of routing and/or QoS handling may allow proactive configuration of intermediate on-path IAB-nodes, i.e. configuration may be independent of UE-bearer establishment/release. In an example, for both adaptation layer placements, RLC ARQ may be pre-processed on TX side.

In an example, for RLC AM, ARQ may be conducted hop-by-hop along access and backhaul links. ARQ may be supported end-to-end between UE and IAB-donor. RLC segmentation may be a just-in-time process, and/or it may be conducted in a hop-by-hop manner.

A type of multi-hop RLC ARQ and adaptation-layer placement may have interdependence: for end-to-end ARQ, adaptation layer may be integrated with MAC layer or placed above MAC layer; and/or hop-by-hop ARQ may or may not have interdependence.

In an example, different IAB architecture options may have impact on scheduling and/or QoS in downlink and/or uplink directions. In an example, adaptation layer may be placed above an RLC and/or above a MAC.

In an example, control plane (CP) signaling across wireless backhaul-link may use the same routing and/or QoS enforcement mechanisms as for user plane (UP) traffic. Priorities and/or QoS requirements of CP signaling may be different from UP traffic.

In an example, signaling between an MT on an IAB-node and a central unit control plan (CU-CP) on an IAB-donor may use RRC protocol. Signaling between DU on an IAB-node and a CU-CP on an IAB-donor may use an F1-AP protocol. IAB specific enhancements to RRC and F1-AP may be supported.

In an example, RRC and F1-AP connections may be secured over wireless backhaul links. An RRC connection may have at least the same level of protection on a wireless backhaul link as on an access link. In an example, an F1-AP connection may have at least the same level of protection on a wireless backhaul link as an RRC connection. In an example, the same level of protection for F1-AP as for RRC may be supported.

In an example, for CP signaling protection: PDCP may be used to protect RRC; and/or PDCP may be employed to protect F1-AP over a wireless backhaul. CP signaling protection based on using NDS may be supported.

In an example of architecture 1a, UE's and/or MT's UP and/or RRC traffic may be protected via PDCP over a wireless backhaul. A CP protection mechanism may be defined to protect F1-AP traffic over a wireless backhaul.

In an example, for alternative 1 of architecture 1a, FIG. 25 shows protocol stacks for UE's RRC, MT's RRC, and/or DU's F1-AP. In an example, an adaptation layer may be placed on top of RLC. On IAB-node's access link, an adaptation layer may or may not be included. In an example of alternative 1 of architecture 1a, UE's and/or MT's RRC may be carried over SRB. On UE's and/or MT's access link, SRB may use an RLC-channel. On wireless backhaul links, SRB's PDCP layer may be carried over RLC-channels with adaptation layer. An adaptation layer placement in an RLC channel may be the same for C-plane as for U-plane. Information carried on an adaptation layer may be different for signaling radio bearer (SRB) than for data radio bearer (DRB). DU's F1-AP may be encapsulated in RRC of a collocated MT. F1-AP may be protected by PDCP of an underlying SRB. An IAB-donor may use native F1-C stack.

In an example, for alternative 2 of architecture 1a, FIG. 26 shows protocol stacks for UE's RRC, MT's RRC, and/or DU's F1-AP. In an example, an adaptation layer may reside on top of RLC. On IAB-node's access link, an adaptation layer may or may not be included. In an example of alternative 2 of architecture 1a, UE's and/or MT's RRC may be carried over SRB. On UE's and/or MT's access link, an SRB may use an RLC-channel. On a wireless backhaul link, PDCP of RRC's SRB may be encapsulated into F1-AP. DU's F1-AP may carried over an SRB of a collocated MT. F1-AP may be protected by this SRB's PDCP. On wireless backhaul links, PDCP of F1-AP's SRB may be carried over RLC-channels with adaptation layer. An adaptation layer placement in an RLC channel may be the same for C-plane as for U-plane. Information carried on an adaptation layer may be different for SRB than for DRB. An IAB-donor may use native F1-C stack.

In an example, for alternative 3 of architecture 1a, FIG. 27 shows protocol stacks for UE's RRC, MT's RRC, and/or DU's F1-AP. In an example, an adaptation layer may reside on top of RLC. On IAB-node's access link, an adaptation layer may or may not be included. In an example of alternative 3 of architecture 1a, UE's and/or the MT's RRC may be carried over SRB. On UE's and/or MT's access link, RRC's SRB may use an RLC-channel. On wireless backhaul links, SRB's PDCP layer may be carried over RLC-channels with adaptation layer. An adaptation layer placement in an RLC channel may be the same for C-plane as for U-plane. Information carried on an adaptation layer may be different for SRB than for DRB. DU's F1-AP may be carried over an SRB of a collocated MT. F1-AP may be protected by SRB's PDCP. On wireless backhaul links, PDCP of an SRB may be carried over RLC-channels with adaptation layer. An IAB-donor may use native F1-C stack.

In an example, for alternative 4 of architecture 1a, FIG. 28 shows protocol stacks for UE's RRC, MT's RRC, and/or DU's F1-AP. In an example, an adaptation layer may reside on top of RLC and/or may carry an IP-layer. In an example of alternative 4 of architecture 1a, an IP-layer carried by adapt may be connected to fronthaul's IP-plane through a routing function at an IAB-donor DU. On an IP-layer, IAB-nodes may hold IP-addresses, which may be routable from an IAB-donor CU-CP. An extended IP-plane may allow native F1-C to be used between IAB-node DU and IAB-donor CU-CP. Signaling traffic may be prioritized on an IP routing plane using DSCP markings. F1-C may be protected via NDS, e.g. via D-TLS. UE's and/or MT's RRC may use SRB, which may be carried over F1-C.

In an example, for an alternative of architecture 1b, FIG. 29 shows protocol stacks for UE's RRC, MT's RRC, and/or DU's F1-AP. In an example, an adaptation layer carrying DRB's PDCP may reside on top of RLC. On IAB-node's access link, an adaptation layer may or may not be included. In an example of an alternative of architecture 1b, UE's and/or MT's RRC may be carried over SRB. On a wireless backhaul, SRB's PDCP may be carried over native F1-C. DUs on IAB-node and/or IAB-donor may use native F1-C stack. Over wireless backlinks, an IP-layer of native F1-C stack may be provided by a PDU session. A PDU-session may be established between an MT collocated with a DU and/or a UPF. A PDU session may be carried by a DRB between an MT and a CU-UP. Between CU-UP and UPF, a PDU-session may be carried via NG-U. IP transport between UPF and CU-CP may be provided by PDU-session's DN. IP transport may be protected. Protection of F1-C transport across a DN between UPF and CU-CP may be supported.

In an example, IAB topologies may comprise a spanning tree (ST) and/or a directed acyclic graph (DAG). Directionality of Uu-backhaul link, defined by uplink and downlink, may be aligned with the hierarchy of ST and/or DAG. For ST, an IAB-node may have one parent node, which may be an IAB-node and/or an IAB-donor. For ST, an IAB-node may be connected to one IAB-donor at a time, and/or one route may exist between IAB-node and IAB-donor. For DAG, an IAB-node may be multi-connected, i.e., an IAB-node may have links to multiple parent nodes. For DAG, an IAB-node may have multiple routes to a node, e.g. an IAB-donor. For DAG, an IAB-node may have redundant routes to a node via multiple parents. In an example, multi-connectivity (e.g. dual-connectivity) and/or route redundancy may be used. Redundant routes may be used concurrently, e.g., to achieve load balancing, reliability, etc.

In an example, for architecture group 1, as shown in FIG. 30, routes for an IAB-node may pertain to: the same IAB-donor DU, and the same IAB-donor CU-CP and CU-UP (FIG. 30 a); different IAB-donor DUs, and same IAB-donor CU-CP and CU-UP (FIG. 30 b); different IAB-donor DUs, different IAB-donor CU-UP, and same IAB-donor CU-CP (FIG. 30 3); different IAB-donor DUs, CU-CP and CU-UP (FIG. 30 d).

In an example, for architecture group 2, as shown in FIG. 31, routes for an IAB-node may pertain to the same IP domain and/or different IP domains. For at least some of these topologies, IP address management and/or procedures for topology adaptation may be supported.

In an example, an IAB-node may authenticate with operator's network and/or may establish IP connectivity to reach OAM functionality for OAM configuration. The authentication phase may comprise discovery and/or selection of a serving node, which may be an IAB-donor and/or an IAB-node. An IAB-node may retrieve IAB information, e.g. from OAM and/or via RAN signaling such as OSI or RRC. The authentication phase may comprise setting up connectivity to RAN nodes and/or core network (CN). The authentication phase may involve an MT function on an IAB-node.

In an example, IAB-node's DU, gNB, and/or UPF may be set up together with interfaces to RAN-nodes and/or CN. The interface setting-up phase may be performed before an IAB node start serving UEs and/or before IAB-nodes connect. In an example, for architectures 1a and 1b, the interface setting-up phase may comprise setup of IAB-node's DU and/or F1-establishment to IAB-donor's CU-CP and/or CU-UP. In an example, for architecture 2a, the interface setting-up phase may comprise setup of IAB-node's gNB and/or UPF, and/or integration into PDU session forwarding layer across a wireless backhaul. In an example, the interface setting-up phase may comprise IAB-node's integration into topology and/or route management.

In an example, an IAB-node may provide service to UEs and/or to integrated IAB-nodes. UEs may or may not distinguish access to the IAB-node from access to gNBs (e.g. eNBs, RAN).

In an example, IAB architectures of IAB-donor DU and/or IAB-donor CU may be based on CU/DU architectures of a gNB (e.g. RAN). Modifications to the IAB-node DU that supports F1*-U over a wireless backhaul may be supported.

In an example, as shown in FIG. 32, an IAB-node has connections with a parent node, child node and/or a wireless device (e.g. UE). An IAB-node may be connected to IAB-donor (e.g. parent node of the IAB-node) via a downlink parent backhaul (e.g. F1 interface, NG interface, S1 interface, Uu interface, Xn interface) and/or an uplink parent backhaul (e.g. F1 interface, NG interface, S1 interface, Uu interface, Xn interface). An IAB-node may be connected to a child node of the IAB-node via a downlink child backhaul (e.g. F1 interface, NG interface, S1 interface, Uu interface, Xn interface) and/or an uplink child backhaul (e.g. F1 interface, NG interface, S1 interface, Uu interface, Xn interface). An IAB-node may be connected to a wireless device via a downlink access (e.g. Uu interface) and/or an uplink access (e.g. Uu interface).

In an example, a wireless device in an RRC connected state may experience (and/or determine) a connection failure from at least one cell of a base station. A connection failure may comprise a radio link failure (RLF) and/or a handover failure (HOF).

In an example, a wireless device may determine an RLF when one of following criteria are met: expiry of a timer started after indication of radio problems (e.g. out of sync) from a physical layer (if radio problems are recovered before the timer is expired, the UE may stop the timer); random access procedure failure; RLC failure (e.g. a number of retransmission is over a threshold); and/or the like. In an example, after the RLF is declared, the wireless device may: stay in an RRC_CONNECTED state (e.g. RRC connected state); select a suitable cell and initiate RRC re-establishment; enter an RRC_IDLE state (e.g. RRC idle state) if a suitable cell wasn't found within a certain time after the RLF was declared; stay at an RRC_INACTIVE state (e.g. RRC inactive state) if a suitable cell wasn't found within a certain time after the RLF was declared; and/or the like.

In an example, a behavior of a wireless device associated with the RLF may comprise two phases. A first phase may be started upon a radio problem detection; may lead to the RLF detection; may not initiate a UE based mobility; may be based on a timer (e.g. T1) or other criteria (e.g. counting); and/or the like. A second phase may be started upon the RLF or the HOF; may leads to an RRC idle state of the wireless device; may initiate a UE based mobility; may be based on a timer (e.g. T2); and/or the like. In an example, the wireless device in a normal operation of an RRC connected state may experience the first phase comprising the radio problem detection and no recovery during the T1, and/or may experience the second phase comprising no recovery during the T2. The second phase may be followed by an RRC idle state (e.g. the wireless device may go to an RRC idle state). During the normal operation, the first phase, and/or the second phase, the wireless device may be considered as being in an RRC connected state. In an example, the RLF may be considered as occurring between the first phase and the second phase (e.g. at an ending time of the first phase and/or at the starting time of the second phase).

In an example, upon detecting physical layer problems for a PCell, i.e. upon receiving N310 consecutive out-of-sync indications from lower layers, a wireless device may start a timer, T310. Upon receiving N311 consecutive in-sync indications from lower layers for the PCell, and/or upon triggering a handover procedure and upon initiating a connection re-establishment procedure, a wireless device may stop T310. In an example, when a timer, T310, is expired, if security is not activated, a wireless device may go to RRC_IDLE state; and/or if security is activated, a wireless device may initiate a connection re-establishment procedure.

In an example, upon initiating an RRC connection re-establishment procedure, a wireless device may start a timer, T311. Upon selecting a suitable cell of LTE/5G/another RAT, a wireless device may stop T311. If T311 is expired, a wireless device may enter an RRC_IDLE state.

In an example, a wireless device may detect the HOF that may occur due to a too early handover, a too late handover, a handover to wrong cell, and/or the like. In case of the too early handover, a radio link failure may occur shortly after a successful handover from a source cell to a target cell, and/or a handover failure may occur during a handover procedure. In case of the too early handover, the wireless device may attempt to reestablish a radio link connection in the source cell. In case of the too late handover, a radio link failure may occur after the wireless device may stay for a long period of time in a cell (e.g. a radio link failure may occur because a serving base station may not initiate a handover for the wireless device when a radio link quality is not good enough to serve the wireless device in a current cell.), and/or the wireless device may attempt to reestablish a radio link connection in a different cell. In case of the handover to wrong cell, a radio link failure may occur shortly after a successful handover from a source cell to a target cell, and/or a handover failure may occur during a handover procedure. In case of the handover to wrong cell, the UE may attempt to reestablish a radio link connection in a cell other than the source cell and the target cell. In an example, the “successful handover” may refer to wireless device's state of a successful completion of a random access (RA) procedure.

In an example, to resolve a problem of a connection failure (e.g. RLF and/or HOF), a wireless device and/or a network (e.g. a base station, a base station CU, a base station DU, a gNB, an eNB, a core network, and/or the like) may trigger one or more of following functions: a detection of the connection failure after an RRC reestablishment attempt; a detection of the connection failure after an RRC connection setup; a retrieval of information needed for problem analysis; and/or the like. Triggering of each of the functions may be optional, and/or may depend on situation and/or implementation.

In an example embodiment, a wireless device may be served via an intermediate network node (e.g. integrated access and backhaul (IAB) node, IAB-donor, base station, gNB, base station distributed unit (gNB-DU), relay node), which may be connected via a radio backhaul link to a radio access network (e.g. gNB, gNB-CU, IAB-donor, eNB, base station, RAN node). The radio access network connected to the intermediate network node may have a wireline connection with a core network node (e.g. AMF, SMF, UPF, MME, SGW, PGW). The wireless device may be served by the radio access network and/or the core network node via the intermediate network node. When serving a wireless device via an intermediate network node, link quality of a radio backhaul link of the intermediate network node may affect serving the wireless device. In an example, a blockage/failure/problem of a radio backhaul link may cause disability of packet transmission and/or service for the wireless device. In an example, a blockage/failure/problem of a radio backhaul link may cause a connection failure (e.g. radio link failure/handover failure) the wireless device. Implementation of existing communication mechanism for a radio link failure (RLF) report may increase inefficient operations in configuring radio resource configuration parameters depending on a status of a radio backhaul link. The existing technology may increase connection latency and packet transmission delay of wireless devices due to improper radio parameter configurations. The existing technology may decrease access reliability of wireless devices.

Implementation of example embodiments may enhance cellular communication reliability by providing an RLF report mechanism considering backhaul link information of wireless devices that experiences a connection failure when being served by an IAB-node. Example embodiment may support communication of network nodes and/or wireless devices for status information of a radio backhaul link. Example embodiment may support radio configurations of network nodes and/or wireless devices based on status information of a radio backhaul link. Implementation of example embodiments may decrease connection latency and/or packet transmission delay of wireless devices. Implementation of example embodiments may increase access/communication reliability and/or mobility performance of wireless devices.

In an example embodiment, as shown in FIG. 33 and/or FIG. 34, a wireless device (e.g. UE, IAB-node) may be served by a first network node (e.g. IAB-donor, gNB-CU, and/or gNB, eNB) and/or a second network node (e.g. IAB-nodel, gNB-DU, and/or gNB, eNB). The second network node may be connected to the first network node via a first radio link (e.g. link1, radio backhaul link, backhaul link, Uu interface, F1 interface, NG interface, S1 interface) at least to serve the wireless device. In an example, the first radio link may comprise one or more radio links connected via one or more network nodes (e.g. one or more IAB-donors/IAB-nodes). In an example, a failure of the first radio link may comprise at least one failure of the one or more radio links. In an example, the wireless device may be connected to the second network node via a second radio link (e.g. link2, Uu interface). In an example, the second network node may provide a primary cell for the wireless device. In an example, the second network node may be an intermediate network node between the first network node and the wireless device.

In an example, the first network node may comprise at least one of a base station, a base station (e.g. gNB, eNB), a central unit (e.g. gNB-CU), and/or an IAB-donor (e.g. relay donor node). In an example, the second network node may comprise at least one of a base station (e.g. gNB, eNB), a base station distributed unit (e.g. gNB-DU), and/or an IAB-node (e.g. relay node).

In an example, a third network node (e.g. a second base station, gNB2, gNB, eNB) may or may not be a neighboring base station of the first network node and/or the second network node. The third network node may be connected to the first network node via an Xn interface (e.g. X2 interface) and/or via one or more NG interfaces (e.g. via one or more AMFs, S1 interface, one or more MMEs, one or more core network nodes). The third network node may comprise one or more IAB-node and/or one or more IAB-donor. The third network node may comprise one or more gNB-CUs and/or one or more gNB-DUs.

In an example, an IAB-donor (e.g. the first network node) may comprise gNB functions (e.g. PHY/MAC/RLC/PDCP/SDAP layer), gNB-CU functions (e.g. at least PDCP/SDAP layer), and/or UPF functions for the wireless device and/or an IAB-node depending on implementation of IAB architecture group. In an example, an IAB-node (e.g. the second network node) may comprise gNB functions (e.g. PHY/MAC/RLC/PDCP/SDAP layer) and/or gNB-DU functions (e.g. at least MAC/PHY layer) for the wireless device depending on implementation of IAB architecture group. In an example, the wireless device may be an IAB-node (or IAB-donor) serving one or more wireless devices and/or one or more IAB-nodes.

In an example, the first network node may comprise at least one of a base station, an integrated access and backhaul donor (IAB-donor), and/or an integrated access and backhaul node (IAB-node). In an example, the second network node may comprise at least one of an integrated access and backhaul donor (IAB-donor) and/or an integrated access and backhaul node (IAB-node). In an example, the third network node may comprise at least one of an integrated access and backhaul donor (IAB-donor) and/or an integrated access and backhaul node (IAB-node). In an example, the wireless device may comprise at least one of a user equipment, an integrated access and backhaul node (IAB-node), and/or an integrated access and backhaul donor (IAB-donor).

In an example, downlink packets of the wireless device may be transmitted from the first network node to the wireless device via the second network node. The downlink packets may be PDCP layer packets. The first network node may receive data of the downlink packets from one or more UPFs and/or one or more IAB-donors. In an example, uplink packets of the wireless device may be transmitted from the wireless device to the first network node via the second network node. The uplink packets may be PDCP layer packets. The first network node may forward data of the uplink packets to one or more UPFs and/or one or more IAB-donors.

In an example, as shown in FIG. 35, FIG. 36, FIG. 37, FIG. 38, FIG. 39, FIG. 40, FIG. 41, FIG. 42, FIG. 43, and/or FIG. 44, the wireless device may receive, from a first network node (e.g. and/or from the second network node), at least one radio resource control (RRC) message comprising configuration parameters of a first cell of a second network node. In an example, the first cell may be a primary cell of the wireless device. In an example, the first cell may be a SpCell/PSCell of the wireless device.

In an example, if the first network node (e.g. IAB-donor, gNB-CU) provides an RRC layer for the wireless device (e.g. in case of IAB architecture group 1, and/or IAB architecture 2c), the at least one RRC message may be transmitted by the first network node to the second network node (e.g. IAB-node, gNB-DU) via the first radio link, and/or the second network node may forward/transmit the at least one RRC message to the wireless device via the second radio link. In an example, if the second network node (e.g. IAB-node, gNB) provides an RRC layer for the wireless device (e.g. in case of IAB architecture group 2), the at least one RRC message may be transmitted by the second network node to the wireless device via the second radio link.

In an example, the at least one RRC message may comprise at least one of an RRC reconfiguration message, an RRC connection reconfiguration message, an RRC connection reestablishment message, an RRC connection setup message, an RRC connection resume message, a downlink RRC message, a relay node reconfiguration message, and/or the like. In an example, the at least one RRC message may comprise at least one of a UE identifier (e.g. TMSI, C-RNTI, F1 UE identifier, NG UE identifier, IMSI) of the wireless device, a cell identifier (e.g. physical cell identifier, PCI, global cell identifier, GCI, CGI) of the first cell, cell information (e.g. cell index, cell group configuration, radio link failure timers and constants, RLM in-sync/out-of-sync threshold, reconfiguration with sync comprising t304 value, RACH configuration parameters comprising a preamble index and/or RACH resources, carrier frequency information, bandwidth part configuration parameters, beam configuration parameters of SS beam and/or CSI-RS beam, transmission power configuration parameter comprising p-MAX/p-MgNB/p-SgNB, and/or the like) of the first cell, a cell identifier (e.g. physical cell identifier, PCI, global cell identifier, GCI, CGI) of at least one cell, cell information (e.g. cell index, cell group configuration, radio link failure timers and constants, RLM in-sync/out-of-sync threshold, reconfiguration with sync comprising t304 value, RACH configuration parameters comprising a preamble index and/or RACH resources, carrier frequency information, bandwidth part configuration parameters, beam configuration parameters of SS beam and/or CSI-RS beam, transmission power configuration parameter comprising p-MAX/p-MgNB/p-SgNB, and/or the like) of the at least one cell, a bearer identifier of a bearer, a logical channel identifier (index) of the bearer, a PDU session identifier of the bearer, a QoS flow identifier of the bearer, an IAB-node identifier of the second network node, an IAB-donor identifier of the first network node, and/or the like. In an example, the configuration parameters (e.g. of the at least one RRC message) of the first cell may comprise the cell identifier of the first cell and/or the cell information of the first cell.

In an example, the at least one RRC message may comprise one or more system information blocks (e.g. master information block, system information block type 1, system information block type 2, system information block type 3, etc.). In an example, the one or more system information blocks may comprise the cell identifier of the first cell, the cell information of the first cell, the cell identifier of the at least one cell, the cell information of the at least one cell, and/or the like. In an example, the at least one cell may comprise one or more secondary cells (e.g. of master cell group and/or of secondary cell group) of the wireless device.

In an example, the at least one RRC message may comprise at least one of an rrc-transactionidentifier information element (IE), a radio resource configuration dedicated IE comprising one or more radio resource configuration parameters, measurement configuration parameters, mobility control information parameters, one or more NAS layer parameters, security parameters, antenna information parameters, secondary cell addition/modification parameters, secondary cell release parameters, WLAN configuration parameters, WLAN offloading configuration parameters, LWA configuration parameters, LWIP configuration parameters, RCLWI configuration parameters, sidelink configuration parameters, V2X configuration parameters, uplink transmission power configuration parameters (e.g. p-MAX, p-MeNB, p-SeNB), a power control mode information element, secondary cell group configuration parameters, and/or the like.

In an example, in response to receiving the at least one RRC message, the wireless device may transmit at least one acknowledge/response message (e.g. at least one RRC acknowledge/response message) to the first network node (e.g. in case of IAB architecture group 1 and/or IAB architecture 2c) via the second network node and/or to the second network node (e.g. in case of IAB architecture group 2).

The at least one acknowledge/response message may comprise at least one RRC acknowledge/response message. In an example, the at least one acknowledge/response message may comprise at least one of: an uplink RRC message, a relay node reconfiguration complete message, an RRC connection reconfiguration complete message, an RRC connection reestablishment complete message, an RRC connection resume complete message, an RRC connection setup complete message, and/or the like. The at least one acknowledge/response message may indicate whether one or more elements (e.g. one or more of the configuration parameters of the first cell) of the at least one RRC message are successfully configured by the wireless device. The at least one acknowledge/response message may indicate whether the bearer is successfully established by the wireless device.

In an example, the wireless device may transmit, to the second network node, packets based on the configuration parameters (e.g. via the first cell and/or via at least one cell) and/or one or more elements of the at least one RRC message (e.g. based on RLC/PDCP/MAC configuration parameters and/or physical layer configurations received via the at least one RRC message, for example transmit with a power level corresponding to the p-MAX) received from the first network node and/or from the second network node. The second network node may forward/transmit the packets to the first network node. The first network node may forward/transmit packets (e.g. data of the packets) to one or more UPFs and/or to one or more serving gateways. In an example, the wireless device may transmit, to the second network node, packets via the bearer, e.g. based on the at least one RRC message. The second network node may forward the packets (or data of the packets) (e.g. uplink packets) to the first network node via the bearer.

In an example, the wireless device may receive, from the second network node, packets based on the configuration parameters (e.g. via the first cell and/or via at least one cell) and/or one or more elements of the at least one RRC message (e.g. based on RLC/PDCP/MAC configuration parameters and/or physical layer configurations received via the at least one RRC message, for example, receive packets via resources assigned based on resource coordination parameters that are configured by the at least one RRC message) received from the first network node and/or from the second network node. The second network node may receive the packets from the first network node. The first network node may receive packets (e.g. data of the packets) from one or more UPFs and/or from one or more serving gateways. In an example, the wireless device may receive, from the second network node, packets via the bearer, e.g. based on the at least one RRC message. The second network node may receive the packets (or data of the packets) (e.g. downlink packets) from the first network node via the bearer.

In an example, the wireless device may determine a connection failure from the first network node (e.g. and/or from the second network node) based on a backhaul link failure (e.g. backhaul link problem, backhaul link blockage). In an example, the connection failure may comprise at least one of a radio link failure and/or a handover failure. In an example, the connection failure may comprise the backhaul link failure. In an example, the backhaul link failure may comprise a failure (e.g. problem, blockage, disability, unavailability, disconnection, outage) of a first radio link established between the first network node and the second network node. In an example, the first radio link may comprise one or more radio links connected via one or more network nodes. The failure (e.g. problem, blockage, disability, unavailability, disconnection, outage) of the first radio link may indicate at least one failure of the one or more radio links.

The backhaul link failure may comprise (e.g. and/or may occur because of) a connection failure (e.g. radio link failure, handover failure) of the second network node. The backhaul link failure may comprise (e.g. and/or may occur because of) a blockage (e.g. failure, problem, disability, unavailability, disconnection, outage) of the second network node (e.g. temporary disability of signaling with the first network node). The blockage of the first radio link (e.g. and/or the backhaul link failure) may comprise at least one of: a beam failure of a cell (e.g. a cell serving the second network node); a beam failure recovery failure of a cell (e.g. a cell serving the second network node); a time alignment timer expiration of a cell (e.g. a cell serving the second network node); a first number of radio link control (RLC) packet retransmissions (and/or HARQ retransmission) of the second network node being equal to or larger than a first count value; a reference signal received power/quality (RSRP/RSRQ) of the second network node from a cell (e.g. a cell serving the second network node) being equal to or smaller than a first power/quality value; an expiration of a blockage timer (e.g. time of the blockage timer passes since a blockage is determined by the second network node); and/or the like.

In an example, in case of IAB architecture group 1 and/or IAB architecture group 2c (e.g. RRC function locates at an IAB-donor (e.g. at the first network node)), the connection failure of the wireless device from the first network node may comprise an RRC connection failure (e.g. and/or RLC/MAC layer connection failure, F1 connection failure). In an example, in case of IAB architecture group 2 (e.g. RRC function locates at an IAB-node (e.g. at the second network node)), the connection failure of the wireless device from the first network node may comprise a backhaul link problem (and/or failure) (e.g. NG connection failure, the backhaul link failure).

In an example, the wireless device may determine the backhaul link failure based on indication from the second network node and/or based on upper layer packet transmission status (e.g. RLC packet transmission failure, not receiving ACK from transmitted RLC packets, receiving NACK for transmitted RLC packets, and/or number of RLC packet retransmissions being equal to or larger than a configured value).

In an example, the wireless device may receive, from the second network node, a backhaul link failure information indicating the failure (e.g. problem, blockage) of the first radio link established between the first network node and the second network node. In an example, the wireless device may determine the connection failure based on the backhaul link failure information. In an example, the wireless device may receive, from the second network node, a connection release indication. The connection release indication may comprise the backhaul link failure information. The connection release indication may command/indicate the wireless device to release connection from the second network node (e.g. the first cell) and/or from the first network node. The second network node may transmit the connection release indication in response to determining the backhaul link failure (e.g. problem) indicated via the backhaul link failure information.

In an example, the wireless device may receive the connection release indication and/or the backhaul link failure information via at least one of a medium access control control element (MAC CE), a physical layer command comprising downlink control information (DCI), an adaptive layer indication, one or more user plane packets, and/or a radio resource control message (e.g. RRC connection release message, downlink RRC message, RRC connection reconfiguration message). In an example, the adaptive layer indication may comprise at least one of: at least one of one or more (e.g. adaptive layer) packets (e.g. comprising data of the packets); and/or a header of at least one of one or more (e.g. adaptive layer) packets (e.g. comprising data of the packets).

In an example, the backhaul link failure information may comprise at least one of: a first node identifier of the first network node; a second node identifier of the second network node; a failure (e.g. blockage, problem) type (e.g. comprising at least one of: a temporary blockage; a failure of at least one of multiple backhaul links of the second network node; and/or a failure of all backhaul links of the second network node) of the back haul link failure; a timer value for determining an integrated access and backhaul node failure (e.g. the wireless device may determine the backhaul link failure in response to expiration of a timer of the timer value; the timer may start in response to receiving the backhaul link failure information); an indication parameter indicating a state transition into a dormant state of one or more cells of the second network node; an indication parameter indicating release of one or more cells of the second network node; a cause value of the failure (e.g. RLF cause, RLC retransmission number, failure timer expiration, beam failure recovery failure, random access failure, time alignment timer expiration) of the first radio link; a bearer identifier of the bearer affected by the failure of the first radio link; one or more beam identifiers of one or more beams of a cell (e.g. employed by the second network node) (e.g. a cell of the first network node) (e.g. a cell causing the failure of the first radio link); one or more bandwidth part (BWP) identifiers of one or more BWPs of a cell (e.g. employed by the second network node) (e.g. a cell of the first network node) (e.g. a cell causing the failure of the first radio link); and/or a cell identifier of a cell (e.g. employed by the second network node) (e.g. a cell of the first network node) (e.g. the a causing the failure of the first radio link).

In an example, the backhaul link failure information may comprise a node identifier of a network node of the one or more network nodes between the first network node and the second network node (e.g. an access radio link of the network node experienced a failure/blockage/problem; e.g. the access radio link of the network node is/comprises one of the (failed) one or more radio links connected via the one or more network nodes between the first network node and the second network node).

In an example, the indication of the backhaul link failure information may comprise an indication parameter (e.g. via MAC CE) indicating a state transition into a dormant state of one or more cells of the second network node. In an example, if the indication parameter indicates that all cells of the second network node for the wireless device or a part of the all cells transitions into a dormant state, the wireless device may consider the first radio link experiences a blockage (e.g. failure).

In an example, the indication of the backhaul link failure information may comprise an indication parameter (e.g. via MAC CE) indicating deactivation of one or more cells of the second network node. In an example, if the indication parameter indicates that all cells of the second network node for the wireless device or a part of the all cells are deactivated, the wireless device may consider the first radio link experiences a blockage (e.g. failure).

In an example, the second network node may determine the failure (e.g. blockage) of the first radio link based on at least one of: a radio link failure (e.g. from the first network node and/or from one or more network node connecting the first network node and the second network node), a handover failure, a beam failure of a cell serving the second network node; a beam failure recovery failure of a cell (e.g. a cell serving the second network node; e.g. a cell of the first network node); a random access failure via a cell (e.g. a cell serving the second network node; e.g. a cell of the first network node); a time alignment timer expiration of a cell (e.g. a cell serving the second network node; e.g. a cell of the first network node); a first number of radio link control (RLC) packet retransmissions (or HARQ retransmission) to the first network node being exceeded a first value; a reference signal received power/quality of a cell (e.g. a cell serving the second network node; e.g. a cell of the first network node) and/or one or more beams of a cell (e.g. a cell serving the second network node; e.g. a cell of the first network node) being (e.g. becoming) smaller than or equal to a power/quality value; an expiration of a blockage timer; and/or the like.

In an example, if the second network node determines a beam failure of one or more serving beams of a cell of the first network node (and/or of a cell serving the second network node), the second network node may determine the blockage (e.g. failure) of the first radio link. In an example, when the second network node determines a beam failure of one or more serving beams of a cell of the first network node (and/or of a cell serving the second network node), the second network node may start a blockage timer and/or may determine the blockage (e.g. failure) of the first radio link in response to expiration of the blockage timer.

In an example, if the second network node determines a beam failure recovery failure of one or more beam failure recovery procedures for one or more serving beams of a cell of the first network node (and/or of a cell serving the second network node), the second network node may determine the blockage (e.g. failure) of the first radio link. In an example, when the second network node determines a beam failure recovery failure of one or more beam failure recovery procedures for one or more serving beams of a cell of the first network node (and/or of a cell serving the second network node), the second network node may start a blockage timer and/or may determine the blockage (e.g. failure) of the first radio link in response to expiration of the blockage timer.

In an example, if the second network node determines a random access failure for a cell of the first network node (and/or of a cell serving the second network node), the second network node may determine the blockage (e.g. failure) of the first radio link. In an example, when the second network node determines a random access failure for a cell of the first network node (and/or of a cell serving the second network node), the second network node may start a blockage timer and/or may determine the blockage (e.g. failure) of the first radio link in response to expiration of the blockage timer.

In an example, if the second network node determines a time alignment timer expiration of a cell of the first network node (and/or of a cell serving the second network node), the second network node may determine the blockage (e.g. failure) of the first radio link. In an example, when the second network node determines a time alignment timer expiration of a cell of the first network node (and/or of a cell serving the second network node), the second network node may start a blockage timer and/or may determine the blockage (e.g. failure) of the first radio link in response to expiration of the blockage timer. In an example, when the second network node receives a timing advance command (TAC) from the first network node, the second network node may determine a recovery of the blockage of the first radio link.

In an example, if the second network node determines that a first number of radio link control packet retransmissions (or HARQ retransmission) to the first network node becomes/is equal to or larger than a count value, the second network node may determine the blockage (e.g. failure) of the first radio link. In an example, when the second network node determines that a first number of radio link control packet retransmissions (or HARQ retransmission) to the first network node becomes/is equal to or larger than a count value, the second network node may start a blockage timer and/or may determine the blockage (e.g. failure) of the first radio link in response to expiration of the blockage timer.

In an example, if the second network node determines that a reference signal received power/quality (RSRP/RSRQ) of one or more beams of a cell of the first network node (and/or of a cell serving the second network node) and/or RSRP/RSRQ of a cell of the first network node (and/or of a cell serving the second network node) becomes/is equal to or smaller than a power/quality value, the second network node may determine the blockage (e.g. failure) of the first radio link. In an example, when the second network node determines that a RSRP/RSRQ of one or more beams of a cell of the first network node (and/or of a cell serving the second network node) and/or RSRP/RSRQ of a cell of the first network node (and/or of a cell serving the second network node) becomes/is equal to or smaller than a power/quality value, the second network node may start a blockage timer and/or may determine the blockage (e.g. failure) of the first radio link in response to expiration of the blockage timer.

In an example, in response to determining the backhaul link failure, the wireless device may release the bearer established via the second network node and/or via the first network node. In an example, in response to determining the backhaul link failure, the wireless device may release, the first cell of the second network node. In an example, in response to determining the backhaul link failure, the wireless device may release the first network node and/or the second network node. In an example, in response to determining the backhaul link failure, the wireless device may release configurations of the second network node and/or the first network node (e.g. RRC configurations, MAC configurations, PDCP configurations, RLC configurations, SDAP configuration, PHY configurations, bearer configurations, security configurations, UL/DL resource configurations, power configurations, cell configurations, beam configurations, and/or the like).

In an example, the wireless device may stop, in response to determining the backhaul link failure, transmission of a scheduling request (e.g. resource request for uplink transmission) for the bearer and/or for one or more bearers to the second network node. In an example, in response to determining the backhaul link failure, the wireless device may flush hybrid automatic repeat request buffers of a cell (e.g. the first cell) of the second network node. In an example, in response to determining the backhaul link failure, the wireless device may suspend (e.g. clear, release) configured uplink grant type 1 of a cell of the second network node. In an example, in response to determining the backhaul link failure, the wireless device may clear configured downlink assignment of a cell of the second network node.

In an example, in response to determining the backhaul link failure, the wireless device may clear (e.g. suspend, release) configured uplink grant type 2 of a cell of the second network node. In an example, in response to determining the backhaul link failure, the wireless device may stop (e.g. suspend) a bandwidth part inactivity timer of one or more bandwidth part of a cell of the second network node (e.g. considering the cell is suspended and/or transitioned to dormant/deactivated state). In an example, in response to determining the backhaul link failure, the wireless device may start (e.g. restart) a bandwidth part inactivity timer of a cell of the second network node (e.g. considering receiving the backhaul link blockage information as receiving downlink indication via the cell and/or a corresponding bandwidth part).

In an example, in response to determining the backhaul link failure, the wireless device may stop (e.g. abort) a random access procedure (e.g. ongoing random access procedure) on a cell of the second network node (e.g. stop transmitting a random access preamble, and/or stop monitoring random access response). In an example, in response to determining the backhaul link failure, the wireless device may stop (e.g. suspend) a secondary cell deactivation timer of a cell of the second network node (e.g. considering the cell is suspended and/or transitioned to dormant/deactivated state). In an example, in response to determining the backhaul link failure, the wireless device may start (e.g. restart) a secondary cell deactivation timer of a cell of the second network node (e.g. considering receiving the backhaul link blockage information as receiving downlink indication via the cell). In an example, in response to determining the backhaul link failure, the wireless device may transition a cell of the second network node into a dormant state. In an example, in response to determining the backhaul link failure, the wireless device may deactivate a cell of the second network node.

In an example, in response to determining the backhaul link failure, the wireless device may stop transmitting a transport block to the second network node (e.g. via resources of configured grant Type 1 and/or Type 2). In an example, in response to determining the backhaul link failure, the wireless device may stop transmitting a buffer status report (BSR) to the second network node (e.g. for the first bearer, and/or a logical channel of the first bearer). In an example, in response to determining the backhaul link failure, the wireless device may stop transmitting a power headroom report (PHR) to the second network node.

In an example, in response to determining the backhaul link failure, the wireless device may stop transmitting a sounding reference signal (SRS) via one or more cells to the second network node (e.g. considering the one or more cells are suspended and/or transitioned into dormant/deactivated state). In an example, in response to determining the backhaul link failure, the wireless device may transmit a sounding reference signal (SRS) via one or more cell to the second network node (e.g. for the second network node to monitor an access link).

In an example, in response to determining the backhaul link failure, the wireless device may stop transmitting channel state information (e.g. CSI) to the second network node (e.g. considering a cell of the second network node is suspended and/or transitioned into dormant/deactivated state). In an example, in response to determining the backhaul link failure, the wireless device may transmit channel state information (e.g. CSI) to the second network node (e.g. for a cell transitioned into a dormant state; and/or for the second network node to monitor an access link).

In an example, in response to determining the backhaul link failure, the wireless device may stop transmitting a transport block via an uplink shared channel (e.g. SCH, PUSCH) to the second network node. In an example, in response to determining the backhaul link failure, the wireless device may stop transmitting a preamble via a random access channel (e.g. RACH) to the second network node.

In an example, in response to determining the backhaul link failure, the wireless device may stop monitoring a physical downlink control channel (PDCCH) of a cell of the second network node (e.g. if a recovery and/or failure indication for the first radio link is transmitted via other link (e.g. via the first network node and/or the third network node) or via other cell different from the cell). In an example, in response to determining the backhaul link failure, the wireless device may monitor a physical downlink control channel (PDCCH) of a cell of the second network node (e.g. to receive a recovery and/or failure indication for the first radio link).

In an example, in response to determining the backhaul link failure, the wireless device may stop monitoring a physical downlink control channel (PDCCH) for a cell of the second network node (e.g. considering a cell of the second network node is suspended and/or transitioned into dormant/deactivated state). In an example, in response to determining the backhaul link failure, the wireless device may monitor a physical downlink control channel (PDCCH) for a cell of the second network node (e.g. to receive a recovery and/or failure indication for the first radio link).

In an example, in response to determining the backhaul link failure, the wireless device may stop transmitting a physical uplink control channel (PUCCH) via a cell of the second network node. In an example, in response to determining the backhaul link failure, the wireless device may transmit a physical uplink control channel (PUCCH) via a cell of the second network node (e.g. to indicate release/deactivation/transitioning-into-dormant-state of a cell of the second network node).

In an example, in response to determining the backhaul link failure, the wireless device may transmit at least one of: channel quality information (e.g. CQI) of a cell of the second network node; a precoding matrix index (PMI) of a cell of the second network node; a rank indicator (RI) of a cell of the second network node; a precoding type indicator of a cell of the second network node; a channel state information-reference signal (CSI-RS) resource indicator of a cell of the second network node; and/or channel state information (e.g. CSI) of a cell of the second network node.

In an example, in response to determining the backhaul link failure and/or the connection failure (e.g. and/or in response to release the first cell, the second network node, and/or the first network node), the wireless device may transition an RRC state into the RRC idle state or the RRC inactive state from the RRC connected state.

In an example, in response to determining the backhaul link failure and/or the connection failure (e.g. and/or in response to release the first cell, the second network node, and/or the first network node), the wireless device may select a second cell of the third network node for a radio resource control connection (e.g. RRC connection establishment and/or RRC connection reestablishment). In an example, the wireless device may select the second cell based on measurement results of one or more cells. The one or more cells may comprise at least one of the first cell, the second cell, and/or one or more neighboring cells of the second cell and/or the first cell).

In an example, the third network node may be the first network node. In an example, the third network node may be the second network node. In an example, the third network node may comprise the first network node and the second network node. In an example, the first cell may be the second cell. In an example, the first cell may be a cell different than the second cell.

In an example, the measurement results may comprise a reference signal received power (RSRP) and/or a reference signal received quality (RSRQ) of the one or more cells, an RSRP/RSRQ of one or more beams of the one or more cells, and/or an RSRP/RSRQ of a group of multiple beams of the one or more cells. In an example, in response to the RSRP/RSRQ of the second cell and/or one or more beams (or a group of beams) of the second cell being equal to and/or larger than a power value (e.g. delta dB) and/or a quality value (e.g. gamma dB), the wireless device may select the second cell. In an example, in response to the RSRP/RSRQ of the second cell and/or one or more beams (or a group of beams) of the second cell being equal to and/or larger than the RSRP/RSRQ of one or more neighboring cells of the second cell and/or one or more beams (or a group of beams) of the one or more neighboring cells, the wireless device may select the second cell.

In an example, in response to the second cell not belonging to a list of not-allowed-access cells (e.g. black list cell) and/or belonging to a list of allowed-access cells (e.g. white list cell), the wireless device may select the second cell. The wireless device may select the second cell in response to at least one of: the second cell being of an allowed closed subscriber group; the second cell supporting a necessary network slice (e.g. based on NSSAI/S-NSSAI/network slice information broadcasted via system information block of the second cell and/or based on NSSAI/S-NSSAI required by an application layer of the wireless device); a network capability information (e.g. RAN capability of the third network node and/or the second cell); a numerology/TTI supported by the second cell; a congestion level of the second cell (e.g. the congestion level received via one or more system information blocks of the second cell) and/or the one or more neighboring cells; a backhaul link capacity of the third network node (e.g. information the backhaul link capacity received via one or more system information blocks of the second cell); a backhaul link reliability of the third network node (e.g. information the backhaul link reliability received via one or more system information blocks of the second cell); a backhaul link congestion of the third network node (e.g. information the backhaul link congestion received via one or more system information blocks of the second cell); and/or the like.

In an example, in response to selecting the second cell of the third network node, the wireless device may camp on the second cell. In an example, in response to selecting the second cell of the third network node, the wireless device may initiate a random access procedure by transmitting one or more random access preambles via the second cell to the third network node, e.g. to make an RRC connection with the third network node via the second cell. In an example, the wireless device may transmit, via the second cell, one or more random access preambles. The wireless device may receive, from the third network node, a random access response for the one or more random access preamble. In an example, wireless device may transmit, to the third network node and based on the random access response, a radio resource control (RRC) connection (e.g. reestablishment and/or establishment) request message (e.g. RRC connection reestablishment/setup/resume request message and/or RRC connection reestablishment/setup/resume complete message), e.g. to request an RRC connection reestablishment/setup/resume. In an example, the RRC connection request message may comprise an indication field indicating that the wireless device experienced a connection failure (e.g. RLF, HOF, reconfiguration failure, backhaul link failure/blockage/problem, other failure, and/or the like). The indication field may indicate a cause of the RRC connection reestablishment/setup/resume request (e.g. establishment cause). In an example, the RRC connection request message (e.g. RRC connection reestablishment/setup/resume request message and/or RRC connection reestablishment/setup/resume complete message) may comprise a report indication indicating that the wireless device has a report (e.g. an event to report, RLF report, connection failure report) regarding a connection failure to transmit to a base station (e.g. the third network node).

In an example, the wireless device may transmit, to the third network node, a radio link failure (RLF) report (e.g. connection failure report, backhaul link failure report). The RLF report may comprise a cause value of the connection failure (e.g. and/or the backhaul link failure). The cause value may indicate that the backhaul link failure caused the connection failure.

In an example, the RRC connection request message (e.g. RRC connection reestablishment/setup/resume request message and/or RRC connection reestablishment/setup/resume complete message) may comprise the RLF report. In an example, a report message (e.g. UE information message) transmitted from the wireless device to the third network node may comprise the RLF report.

In an example, the wireless device may receive, from the third network node, a report request message (e.g. a UE information request message) indicating a request to transmit an RLF report to the third network node. The third network node may transmit the report request message based on (and/or in response to) the report indication of the RRC connection request message (e.g. RRC connection reestablishment/setup/resume request message and/or RRC connection reestablishment/setup/resume complete message) received from the wireless device. In an example, in response to receiving the report request message (e.g. a UE information request message), the wireless device may transmit, to the third network node, the report message (e.g. UE information message) comprising the RLF report. In an example, the report request message (e.g. a UE information request message) and/or the report message (e.g. a UE information message) may be an RRC message. In an example, the wireless device may transmit, to the third network node, the RLF report (e.g. the report message and/or the UE information message) in response to receiving, from the third network node, the report request message (e.g. a UE information request message).

In an example, the cause value of the connection failure (e.g. that the wireless device transmits to the third network node via the RLF report) may indicate a reason/cause why the wireless device determined the connection failure and/or the backhaul link failure when served by the second network node and/or the first network node. In an example, the cause value of the connection failure (e.g. that the wireless device transmits to the third network node via the RLF report) may indicate a reason/cause why the second network node determined the backhaul link failure when the second network node served the wireless device. In an example, the cause value may comprise the backhaul link failure information that the wireless device received from the second network node.

In an example, the cause value may comprise one or more fields indicating at least one of: a beam failure of a cell serving the second network node (and/or a cell identifier of the cell; one or more beam identifiers of one or more beams of the beam failure); a beam failure recovery failure of a cell serving the second network node (and/or a cell identifier of the cell; one or more beam identifiers of one or more beams of the beam failure recovery failure); a time alignment timer (TAT) expiration of a cell serving the second network node (and/or a cell identifier of the cell of the TAT expiration); a first number of radio link control (RLC) packet retransmissions (and/or HARQ retransmission) of the second network node being equal to or larger than a first count value; a reference signal received power/quality (RSRP/RSRQ) of the second network node from a cell being equal to or smaller than a first power/quality value (and/or a cell identifier of the cell of the RSRP/RSRQ); an RSRP/RSRQ of the second network node from one or more beams of a cell being equal to or smaller than a second power/quality value (and/or a cell identifier of the cell and/or one or more beam identifiers of the one or more beams of the RSRP/RSRQ); an expiration of a blockage timer (e.g. time of the blockage timer passes since a blockage is determined by the second network node); and/or the like.

In an example, the cause value may indicate that the wireless device determined the backhaul link failure based on indication from the second network node and/or based on upper layer packet transmission status (e.g. RLC packet transmission failure, not receiving ACK from transmitted RLC packets, receiving NACK for transmitted RLC packets, and/or number of RLC packet retransmissions being equal to or larger than a configured value). In an example, the cause value may indicate the failure (e.g. problem, blockage) of the first radio link established between the first network node and the second network node.

In an example, the cause value may indicate/comprise at least one of: a first node identifier of the first network node; a second node identifier of the second network node; a failure (e.g. blockage, problem) type (e.g. comprising at least one of: a temporary blockage; a failure of at least one of multiple backhaul links of the second network node; and/or a failure of all backhaul links of the second network node) of the back haul link failure; a timer value for determining an integrated access and backhaul node failure (e.g. the wireless device may determine the backhaul link failure in response to expiration of a timer of the timer value; the timer may start in response to receiving the backhaul link failure information); an indication parameter indicating a state transition into a dormant state of one or more cells of the second network node; an indication parameter indicating release of one or more cells of the second network node; a cause value of the failure/problem/blockage (e.g. the backhaul link failure) (e.g. RLF cause, RLC retransmission number, failure timer expiration, beam failure recovery failure, random access failure, time alignment timer expiration) of the first radio link; a bearer identifier of the bearer affected by the failure of the first radio link; one or more beam identifiers of one or more beams of a cell (e.g. employed by the second network node) (e.g. a cell of the first network node) (e.g. a cell causing the failure of the first radio link); one or more bandwidth part (BWP) identifiers of one or more BWPs of a cell (e.g. employed by the second network node) (e.g. a cell of the first network node) (e.g. a cell causing the failure of the first radio link); and/or a cell identifier of a cell (e.g. employed by the second network node) (e.g. a cell of the first network node) (e.g. the a causing the failure of the first radio link).

In an example, the cause value may comprise a node identifier of a network node of the one or more network nodes between the first network node and the second network node (e.g. an access radio link of the network node experienced a failure/blockage/problem; e.g. the access radio link of the network node is/comprises one of the (failed) one or more radio links connected via the one or more network nodes between the first network node and the second network node).

In an example, the cause value may comprise one or more fields indicating that the second network node determined the failure (e.g. blockage) of the first radio link based on at least one of: a radio link failure (e.g. from the first network node and/or from one or more network node connecting the first network node and the second network node), a handover failure, a beam failure of a cell serving the second network node; a beam failure recovery failure of a cell (e.g. a cell serving the second network node; e.g. a cell of the first network node); a random access failure via a cell (e.g. a cell serving the second network node; e.g. a cell of the first network node); a time alignment timer expiration of a cell (e.g. a cell serving the second network node; e.g. a cell of the first network node); a first number of radio link control (RLC) packet retransmissions (or HARQ retransmission) to the first network node being exceeded a first value; a reference signal received power/quality of a cell (e.g. a cell serving the second network node; e.g. a cell of the first network node) and/or one or more beams of a cell (e.g. a cell serving the second network node; e.g. a cell of the first network node) being (e.g. becoming) smaller than or equal to a power/quality value; an expiration of a blockage timer; and/or the like.

In an example, the RLF report may comprise at least one of: an identifier of the first network node; an identifier of the second network node; a base station identifier of the second network node; an integrated access and backhaul identifier of the second network node; a transmit and reception point identifier of the second network node; a cell identifier of the first cell; a beam identifier of the first cell; a beam group identifier of one or more beams of the first cell; an F1 wireless device identifier of the wireless device; an information element indicating that the backhaul link failure caused the connection failure; a failure (e.g. blockage, problem) type (e.g. comprising at least one of: a temporary blockage; a failure of at least one of multiple backhaul links of the second network node; and/or a failure of all backhaul links of the second network node); a timer value for determining an integrated access and backhaul node failure; a cause value of the failure of the first radio link; and/or a cell identifier of a cell (e.g. a cell of the first network node and/or a cell employed by the second network node) (e.g. a cell causing the failure of the first radio link).

In an example, the RLF report may comprise at least one of a cell identifier of the first cell, a BWP index of a BWP (e.g. a BWP index of an active BWP when the connection failure is determined), and/or the like. In an example, the RLF report may comprise one or more elements of BWP configuration parameters. The RLF report may comprise parameters (of the BWP configuration parameters) indicating at least one of: a plurality of BWP indexes of a plurality of BWPs; a plurality of BWP bandwidths of a plurality of BWPs; a default BWP index of a default BWP of a plurality of BWPs; a BWP inactivity timer; an initial BWP index of an initial BWP (e.g. initial active BWP) of a plurality of BWPs; a subcarrier spacing for a plurality of BWPs; a cyclic prefix; a number of contiguous PRBs; an index in a set of one or more DL BWPs and/or one or more UL BWPs; a link between a DL BWP and an UL BWP from a set of configured DL BWPs and UL BWPs; a DCI detection to a PDSCH reception timing value; a PDSCH reception to a HARQ-ACK transmission timing value; a DCI detection to a PUSCH transmission timing value; an offset of a first PRB of a DL bandwidth or an UL bandwidth, respectively, relative to a first PRB of a bandwidth; and/or the like.

In an example, the RLF report may comprise one or more report IEs indicating information associated with the connection failure of the wireless device. The one or more report IEs may indicate at least one of: a failed cell identifier of a failed cell (e.g. the first cell and/or a cell that served the second network node at the time of the backhaul link failure/blockage/problem and/or the connection failure), wherein the wireless device experienced the connection failure during employing the failed cell; an RLF cause of the connection failure, wherein the RLF cause indicating at least one of a t310 expiry, a random access problem, a radio link control (RLC) maximum number of retransmissions, or t312 expiry; a wireless device identifier (e.g. C-RNTI, IMEI, TMSI) of the wireless device and/or a network node identifier (e.g. IAB-node identifier, gNB identifier, UE identifier, gNB-DU identifier, C-RNTI) of the second network node at the failed cell; a carrier frequency value of the failed cell; a first time value (e.g. timeConnFailure) indicating time that elapsed since a last handover initialization for the wireless device until the connection failure; a second time value (e.g. timeSinceFailure) indicating time that elapsed since the connection failure (or an establishment failure); a connection failure type indicating whether the connection failure and/or the backhaul link failure is due to an RLF or a handover failure; a measurement result comprising at least one of an RSRP or an RSRQ of the failed cell; a measurement result comprising at least one of an RSRP or an RSRQ of one or more neighboring cells of the failed cell; a quality classification indication 1 bearer indicating the connection failure and/or the backhaul link failure occurred while a bearer with QCI value equal to 1 was configured; a C-RNTI of the wireless device at the first cell; and/or the like.

In an example, the failed cell identifier of the failed cell (e.g. the first cell and/or a cell serving the second network node at the time of the backhaul link failure/blockage/problem) may comprise a global cell identifier (e.g. NCGI, ECGI, CGI, and/or the like), a physical cell identifier (e.g. PCI), and/or the like. In an example, the failed cell may be a primary cell of the wireless device when the connection failure occurred. In an example, the failed cell may be a primary cell of the second network node when the connection failure occurred.

In an example, the cause value of the connection failure may indicate that a cause of determining the connection failure of the wireless device comprises at least one of a t310 expiry, a random access problem (e.g. failure), a radio link control (RLC) maximum number of retransmissions, t312 expiry, and/or the like. In an example, the cause value of the backhaul link failure may indicate that a cause of determining the backhaul link failure of the wireless device (e.g. an access link failure of the second network node) comprises at least one of a t310 expiry, a random access problem (e.g. failure), a radio link control (RLC) maximum number of retransmissions, t312 expiry, and/or the like.

In an example, the t310 expiry may indicate that a timer t310 of the wireless device and/or the second network node expired at the failed cell when the connection failure (e.g. the backhaul link failure) occurred. The timer t310 may start when the wireless device and/or the second network node detects physical layer related problems (e.g. for a primary cell) (e.g. when the wireless device and/or the second network node receives a certain number (e.g. N310) consecutive out-of-sync indications from lower layers). In an example, the timer t310 may stop: when the wireless device and/or the second network node receives a certain number (e.g. N311) consecutive in-sync indications from lower layers (e.g. for a primary cell); upon triggering a handover procedure; upon initiating an RRC connection reestablishment procedure; and/or the like. In an example, at an expiry of the timer t310, if security is not activated, the wireless device and/or the second network node may go to an RRC idle state. In an example, at an expiry of the timer t310, if security is activated, the wireless device and/or the second network node may initiate an RRC connection reestablishment procedure.

In an example, the t312 expiry may indicate that a timer t312 of the wireless device and/or the second network node expired at the failed cell when the connection failure (e.g. the backhaul link failure) occurred. The timer t312 may start upon triggering a measurement report for a measurement identity for which the timer t312 has been configured, while the timer t310 is running. In an example, the timer t312 may stop: upon receiving a certain number (e.g. N311) of consecutive in-sync indications from lower layers; upon triggering a handover procedure; upon initiating a connection re-establishment procedure; upon an expiry of the timer t310; and/or the like. In an example, at an expiry of the timer t312, if security is not activated, the wireless device and/or the second network node may go to an idle state. In an example, at an expiry of the timer t312, if security is activated, the wireless device and/or the second network node may initiate an RRC connection reestablishment procedure.

In an example, the random access problem (e.g. failure) may indicate that the wireless device and/or the second network node experienced one or more random access problems (e.g. random access failures) at the failed cell when the connection failure occurred. In an example, the RLC maximum number of retransmissions may indicate that an RLC layer of the wireless device and/or the second network node tried a maximum number of packet retransmissions when connection failure occurred.

In an example, the wireless device identifier of the wireless device may comprise a C-RNTI at the failed cell (e.g. the first cell), a temporary mobile subscriber identity (TMSI), an International Mobile Subscriber Identity (IMSI), Globally Unique Temporary Identifier (GUTI), and/or the like. In an example, the carrier frequency value may indicate a carrier frequency value of the failed cell. In an example, the carrier frequency value may comprise at least one of an EARFCN, an ARFCN, and/or the like, for example with a maximum value of a maxEARFCN. In an example, the carrier frequency value may be determined according to a band used when obtaining a concerned measurement results.

In an example, the network node identifier of the second network node may comprise a C-RNTI at the failed cell (e.g. a cell (e.g. primary cell of the second network node) that served the second network node at the time of the backhaul link failure and/or the connection failure), a temporary mobile subscriber identity (TMSI), an International Mobile Subscriber Identity (IMSI), Globally Unique Temporary Identifier (GUTI), and/or the like. In an example, the carrier frequency value may indicate a carrier frequency value of the failed cell. In an example, the carrier frequency value may comprise at least one of an EARFCN, an ARFCN, and/or the like, for example with a maximum value of a maxEARFCN. In an example, the carrier frequency value may be determined according to a band used when obtaining a concerned measurement results.

In an example, the measurement result may comprise at least one of a reference signal received power result (RSRP) or a reference signal received quality (RSRQ) of at least one of the failed cell (e.g. the first cell and/or a cell that served the second network node at the time of the backhaul link failure/blockage/problem and/or the connection failure), a last serving cell of the wireless device and/or of the second network node, one or more serving cells of the wireless device and/or of the second network node, one or more neighboring cells (of the wireless device and/or of the second network node) of the failed cell, and/or one or more secondary cells of the wireless device and/or of the second network node. In an example, the wireless device and/or the second network node may determine one or more elements of the measurement result by measuring when (or before/after) the wireless device experiences the connection failure and/or when (or before/after) the second network node experiences the backhaul link failure (e.g. an access link failure of the second network node). In an example, the quality classification indication 1 bearer (e.g. drb-EstablishedWithQCI-1) may indicate that the connection failure and/or the backhaul link failure occurred while a bearer with QCI value 1 was configured.

In an example, the first network node may receive, from the third network node, one or more elements of the radio link failure report. In an example, the first network node may receive, from the third network node, RLF information (comprising the one or more elements) comprising one or more elements of the RLF report. In an example, the first network node may receive the RLF information via one or more Xn interfaces and/or one or more X2 interfaces (e.g. a direct interface between the first network node and the third network node, or indirect interfaces and/or network node(s) between the first network node and the third network node) (e.g. via a handover report message and/or via an RLF indication message). In an example, the first network node may receive the RLF information via one or more NG interfaces and/or one or more S1 interfaces (e.g. via one or more core network nodes (e.g. one or more AMFs, one or more MMEs, one or more SGSNs, one or more GGSNs) between the first network node and the third network node) (e.g. via gNB/eNB/NODE configuration transfer message and/or AMF/MME configuration transfer message; e.g. SON information of gNB/eNB/NODE configuration transfer message and/or AMF/MME configuration transfer message may comprise the RLF information). In an example, the first network node may receive the RLF information via one or more F1 interfaces (e.g. a direct interface between the first network node and the third network node, or indirect interfaces and/or network node(s) between the first network node and the third network node) (e.g. via one or more F1 interface messages).

In an example, as shown in FIG. 34, if the first network node is the third network node, the first network node may receive the RLF report from the wireless device. In an example, if the second network node is the third network node, the first network node may receive the RLF information and/or the RLF report from the second network node. In an example, if an IAB-node served by the first network node is the third network node, the first network node may receive the RLF information and/or the RLF report from the IAB-node served by the first network node.

In an example, the first network node may configure radio resource configuration parameters based on the RLF information and/or the one or more elements of the radio link failure report. In an example, the radio resource configuration parameters may comprise beam configuration parameters for the second network node. In an example, the radio resource configuration parameters may comprise handover triggering parameters for an integrated access and backhaul node. The handover triggering parameters may comprise at least one of a radio signal received quality value (e.g. threshold quality value) and/or a radio signal received power value (e.g. threshold power value).

In an example, based on the RLF information and/or the one or more elements of the radio link failure report, the first network node may determine at least one cell configuration parameter (e.g. the radio resource configuration parameters) of one or more cells of the first network node for one or more wireless devices and/or one or more IAB-nodes based on the RLF information. The one or more cells may comprise the failed cell (e.g. the first cell of the second network node, and/or the cell served the second network node at the time of the connection failure and/or the backhaul link failure). In an example, the at least one cell configuration parameter may comprise at least one of: at least one BWP configuration parameters; at least one transmission power configuration parameter; at least one frequency configuration parameter; at least one beamforming configuration parameter; at least one physical control channel scheduling parameter; at least one antenna configuration parameter; at least one cell selection or reselection configuration parameter for one or more wireless devices; at least one system information; at least one interference control parameter; and/or the like.

In an example, the at least one BWP configuration parameters may be for one or more wireless devices. The at least one BWP configuration parameters may comprise one or more parameters indicating at least one of: a plurality of BWP indexes of a plurality of BWPs; a plurality of BWP bandwidths of a plurality of BWPs; a default BWP index of a default BWP of the plurality of BWPs; a BWP inactivity timer; an initial BWP index of an initial BWP (e.g. initial active BWP) of a plurality of BWPs; a subcarrier spacing for a plurality of BWPs; a cyclic prefix; a number of contiguous PRBs; an index in the set of one or more DL BWPs and/or one or more UL BWPs; a link between a DL BWP and an UL BWP from a set of configured DL BWPs and UL BWPs; a DCI detection to a PDSCH reception timing value; a PDSCH reception to a HARQ-ACK transmission timing value; a DCI detection to a PUSCH transmission timing value; an offset of a first PRB of a DL bandwidth or an UL bandwidth, respectively, relative to a first PRB of a bandwidth; and/or the like.

In an example, if a wireless device and/or an IAB-node (e.g. the second network node) experiences a connection failure during a time that a first BWP of a plurality of BWPs of a cell is an active BWP, a base station (e.g. the first network node) may not configure the first BWP as a default BWP (and/or as an initial BWP) for one or more wireless devices.

In an example, if a channel quality (e.g. RSRP, RSRQ) of a second BWP of a plurality of BWPs of a cell is good (e.g. better than a channel quality of an active BWP) when a wireless device and/or an IAB-node (e.g. the second network node) experiences a connection failure during a time that a first BWP of the plurality of BWPs is an active BWP, a base station (e.g. the first network node) may configure the second BWP as a default BWP (and/or as an initial BWP) for one or more wireless devices.

In an example, the at least one transmission power configuration parameter may comprise a maximum downlink/uplink cell transmission power, a physical downlink control channel (PDCCH) transmission power, one or more power control parameters for uplink and/or downlink, a TPC configuration parameter, an SRS configuration parameter, and/or the like for one or more wireless device and/or for the first network node. In an example, if the first network node determines that the connection failure occurred because of a low transmission power of a PDCCH (e.g. based on the measurement result of the RLF report), the first network node may increase a transmission power of the PDCCH. In an example, if the connection failure occurred because of large interferences on a PDCCH, the first network node may reschedule the PDCCH to be located at other subframes.

In an example, if a wireless device and/or an IAB-node (e.g. the second network node) experiences a connection failure during a time that a first BWP of a plurality of BWPs of a cell is an active BWP, a base station (e.g. the first network node) may increase an uplink/downlink power level (e.g. 0.1 dB increase) for one or more wireless devices (e.g. UEs served in the first cell) when the one or more wireless devices employ the first BWP as an active BWP.

In an example, if a cause of a connection failure of a wireless device and/or an IAB-node (e.g. the second network node) is a random access problem and the wireless device and/or the IAB-node (e.g. the second network node) experiences the connection failure during a time that a first BWP of a plurality of BWPs of a cell is an active BWP, a base station (e.g. the first network node) may not configure the first BWP for a random access preamble transmission of one or more wireless devices.

In an example, if a cause of a connection failure of a wireless device and/or an IAB-node (e.g. the second network node) is an RLC maximum number of retransmissions (e.g. uplink transmission problem; a number of RLC retransmissions is over a threshold value) and the wireless device and/or the IAB-node (e.g. the second network node) experiences the connection failure during a time that a first BWP of a plurality of BWPs of a cell is an active BWP, a base station (e.g. the first network node) may increase an uplink power level for one or more wireless devices when the one or more wireless devices employ the first BWP as an active BWP.

In an example, the at least one frequency configuration parameter may comprise a carrier frequency, a bandwidth, one or more bandwidth part configuration parameters, and/or the like. In an example, if a cell of the first network node experiences large interferences from neighboring cells, the first network node may change an operation frequency to other frequency. In an example, if a certain bandwidth part of a served cell of the first network node experiences large interferences from neighboring cells or other technologies, the first network node may change a default bandwidth part and/or an active bandwidth part of one or more wireless devices to other bandwidth part.

In an example, the at least one beamforming configuration parameter may comprise one or more beamforming direction configuration parameters, one or more beam sweeping configuration parameters, one or more synchronization signal (SS)/reference signal (e.g. CSI-RS) configuration parameters, one or more beam recovery related parameters, one or more BRACH parameter, one or more preamble configuration parameters for beam recovery, one or more random access configuration parameters of one or more beams, and/or the like. In an example, if the connection failure occurred because of a random access failure or a failure of beam recovery procedure (e.g. out-of-sync), the base station (e.g. the first network node) may reschedule random access resources and/or BRACH resources, and/or may reconfigure preambles to reduce random access contentions.

In an example, the at least one physical control channel scheduling parameter may comprise a subframe pattern configuration parameter, a measurement subframe pattern configuration parameter, a transmission type parameter indicating a localized transmission and/or distributed transmission, a resource block assignment configuration parameter, a CSI-RS configuration parameter, and/or the like. In an example, the at least one antenna configuration parameter may comprise default antenna configuration parameters, an antenna port configuration parameter, a number of CRS antenna port parameter, and/or the like. In an example, the at least one cell selection or reselection configuration parameter for one or more wireless devices may comprise one or more power/time threshold parameters for cell selection/reselection of at least one wireless device of the first network node, one or more cell priority configuration parameters for cell selection/reselection, and/or the like. In an example, the connection failure occurred because of a random access failure of the wireless device and/or the second network node, the first network node may increase values of the one or more power/time threshold parameters to make wireless devices avoid the failed cell if the wireless devices and/or an IAB-node (e.g. the second network node) do not satisfy increased thresholds.

In an example, the first network node may reconfigure one or more IEs of the at least one system information comprising at least one of system information type block type 1 to 21 based on the RLF report. In an example, the at least one interference control parameter may comprise one or more almost blank subframe configuration parameters, one or more CoMP interference management related parameters, and/or the like. In an example, if the connection failure and/or the backhaul link failure occurred because of interferences from a neighboring cell of the failed cell, the first network node may schedule resource blocks for the neighboring cell and the failed cell not to use the resource blocks simultaneously.

In an example, the first network node may transmit at least one system information blocks comprising the at least one cell configuration parameter. The at least one system information blocks may be at least one of the system information block type 1 to 21. The first network node may transmit at least one of the at least one cell configuration parameter to one or more wireless devices, e.g. via an RRC message. The one or more wireless device may comprise the wireless device and/or an IAB-node (e.g. the second network node).

In an example, the first network node may transmit, to the second network node, the RLF information and/or the one or more elements of the RLF report (e.g. via F1 interface, Uu interface, NG interface; e.g. via F1 information message, RRC message, NG configuration message). In an example, if the second network node is the third network node, the second network node may receive the RLF report from the wireless device.

In an example, the second network node and/or the first network node may configure radio resource configuration parameters of the second network node based on the RLF information and/or the one or more elements of the radio link failure report. In an example, the radio resource configuration parameters may comprise beam configuration parameters of the second network node to serve one or more wireless device and/or one or more IAB-nodes. In an example, the radio resource configuration parameters may comprise handover triggering parameters for an integrated access and backhaul node. The handover triggering parameters may comprise at least one of a radio signal received quality value (e.g. threshold quality value) and/or a radio signal received power value (e.g. threshold power value).

In an example, based on the RLF information and/or the one or more elements of the radio link failure report, the second network node and/or the first network node may determine at least one cell configuration parameter (e.g. the radio resource configuration parameters) of one or more cells of the second network node to serve one or more wireless devices (e.g. served by the second network node) and/or one or more IAB-nodes (e.g. served by the second network node) based on the RLF information. The one or more cells may comprise the failed cell (e.g. the first cell of the second network node). In an example, the at least one cell configuration parameter may comprise at least one of: at least one BWP configuration parameters; at least one transmission power configuration parameter; at least one frequency configuration parameter; at least one beamforming configuration parameter; at least one physical control channel scheduling parameter; at least one antenna configuration parameter; at least one cell selection or reselection configuration parameter for one or more wireless devices; at least one system information; at least one interference control parameter; and/or the like.

In an example, the at least one BWP configuration parameters may be for one or more wireless devices. The at least one BWP configuration parameters may comprise one or more parameters indicating at least one of: a plurality of BWP indexes of a plurality of BWPs; a plurality of BWP bandwidths of a plurality of BWPs; a default BWP index of a default BWP of the plurality of BWPs; a BWP inactivity timer; an initial BWP index of an initial BWP (e.g. initial active BWP) of a plurality of BWPs; a subcarrier spacing for a plurality of BWPs; a cyclic prefix; a number of contiguous PRBs; an index in the set of one or more DL BWPs and/or one or more UL BWPs; a link between a DL BWP and an UL BWP from a set of configured DL BWPs and UL BWPs; a DCI detection to a PDSCH reception timing value; a PDSCH reception to a HARQ-ACK transmission timing value; a DCI detection to a PUSCH transmission timing value; an offset of a first PRB of a DL bandwidth or an UL bandwidth, respectively, relative to a first PRB of a bandwidth; and/or the like.

In an example, if the wireless device experienced a connection failure during a time that a first BWP of a plurality of BWPs of a cell is an active BWP, a base station (e.g. the first network node and/or the second network node) may not configure the first BWP as a default BWP (and/or as an initial BWP) for one or more wireless devices.

In an example, if a channel quality (e.g. RSRP, RSRQ) of a second BWP of a plurality of BWPs of a cell is good (e.g. better than a channel quality of an active BWP) when the wireless device experienced a connection failure during a time that a first BWP of the plurality of BWPs is an active BWP, a base station (e.g. the first network node and/or the second network node) may configure the second BWP as a default BWP (and/or as an initial BWP) for one or more wireless devices.

In an example, the at least one transmission power configuration parameter may comprise a maximum downlink/uplink cell transmission power, a physical downlink control channel (PDCCH) transmission power, one or more power control parameters for uplink and/or downlink, a TPC configuration parameter, an SRS configuration parameter, and/or the like for one or more wireless device and/or for the second network node. In an example, if the second network node and/or the first network node determines that the connection failure occurred because of a low transmission power of a PDCCH (e.g. based on the measurement result of the RLF report), the second network node and/or the first network node may increase a transmission power of the PDCCH. In an example, if the connection failure occurred because of large interferences on a PDCCH, the first network node may reschedule the PDCCH to be located at other subframes.

In an example, if a wireless device experiences a connection failure during a time that a first BWP of a plurality of BWPs of a cell is an active BWP, a base station (e.g. the second network node and/or the first network node) may increase an uplink/downlink power level (e.g. 0.1 dB increase) for one or more wireless devices (e.g. UEs served in the first cell) when the one or more wireless devices employ the first BWP as an active BWP.

In an example, if a cause of a connection failure of a wireless device is a random access problem and the wireless device experienced the connection failure during a time that a first BWP of a plurality of BWPs of a cell is an active BWP, a base station (e.g. the second network node and/or the first network node) may not configure the first BWP for a random access preamble transmission of one or more wireless devices.

In an example, if a cause of a connection failure of a wireless device is an RLC maximum number of retransmissions (e.g. uplink transmission problem; a number of RLC retransmissions is over a threshold value) and the wireless device experienced the connection failure during a time that a first BWP of a plurality of BWPs of a cell is an active BWP, a base station (e.g. the second network node and/or the first network node) may increase an uplink power level for one or more wireless devices when the one or more wireless devices employ the first BWP as an active BWP.

In an example, the at least one frequency configuration parameter may comprise a carrier frequency, a bandwidth, one or more bandwidth part configuration parameters, and/or the like. In an example, if a cell of the second network node experiences large interferences from neighboring cells, the second network node and/or the first network node may change an operation frequency to other frequency. In an example, if a certain bandwidth part of a served cell of the second network node experiences large interferences from neighboring cells or other technologies, the second network node and/or the first network node may change a default bandwidth part and/or an active bandwidth part of one or more wireless devices to other bandwidth part.

In an example, the at least one beamforming configuration parameter may comprise one or more beamforming direction configuration parameters, one or more beam sweeping configuration parameters, one or more synchronization signal (SS)/reference signal (e.g. CSI-RS) configuration parameters, one or more beam recovery related parameters, one or more BRACH parameter, one or more preamble configuration parameters for beam recovery, one or more random access configuration parameters of one or more beams, and/or the like. In an example, if the connection failure occurred because of a random access failure or a failure of beam recovery procedure (e.g. out-of-sync), the base station (e.g. the second network node and/or the first network node) may reschedule random access resources and/or BRACH resources, and/or may reconfigure preambles to reduce random access contentions.

In an example, the at least one physical control channel scheduling parameter may comprise a subframe pattern configuration parameter, a measurement subframe pattern configuration parameter, a transmission type parameter indicating a localized transmission and/or distributed transmission, a resource block assignment configuration parameter, a CSI-RS configuration parameter, and/or the like. In an example, the at least one antenna configuration parameter may comprise default antenna configuration parameters, an antenna port configuration parameter, a number of CRS antenna port parameter, and/or the like. In an example, the at least one cell selection or reselection configuration parameter for one or more wireless devices may comprise one or more power/time threshold parameters for cell selection/reselection of at least one wireless device of the second network node, one or more cell priority configuration parameters for cell selection/reselection, and/or the like. In an example, the connection failure occurred because of a random access failure of the wireless device, the second network node and/or the first network node may increase values of the one or more power/time threshold parameters to make wireless devices avoid the failed cell if the wireless devices do not satisfy increased thresholds.

In an example, the second network node and/or the first network node may reconfigure one or more IEs of the at least one system information comprising at least one of system information type block type 1 to 21 based on the RLF report. In an example, the at least one interference control parameter may comprise one or more almost blank subframe configuration parameters, one or more CoMP interference management related parameters, and/or the like. In an example, if the connection failure and/or the backhaul link failure occurred because of interferences from a neighboring cell of the failed cell (e.g. the first cell), the second network node and/or the first network node may schedule resource blocks for the neighboring cell and the failed cell not to use the resource blocks simultaneously.

In an example, the second network node and/or the first network node may transmit at least one system information blocks comprising the at least one cell configuration parameter. The at least one system information blocks may be at least one of the system information block type 1 to 21. The first network node may transmit at least one of the at least one cell configuration parameter to one or more wireless devices, e.g. via an RRC message. The one or more wireless device may comprise the wireless device.

In an example, the second network node and/or the first network node may configure handover parameters based on the RLF information and/or the one or more elements of the RLF report. In an example, if a backhaul link connection is not stable (e.g. determining the “not stable is based on the RLF information and/or one or more elements of the RLF report), the second network node and/or the first network node may initiate a handover of a serving wireless devices (and/or a serving IAB-nodes) earlier than the backhaul link connection is stable, e.g. to avoid a connection failure caused by a backhaul link failure. In an example, if an RSRP/RSRQ of the second network node for the first network node (e.g. RSRP/RSRQ measured by the second network node from the first network node; e.g. backhaul link RSRP/RSRQ) is lower than an updated value (e.g. determined based on the RLF information and/or the one or more elements of the RLF report; e.g. if the backhaul link failure occurred when an RSRP/RSRQ of the second network node for the first network node is X dB, the updated value may be configured as X dB or a higher value than X dB), the second network node and/or the first network node may initiate a handover of a wireless device (served by the second network node) having a stable access link connection with the second network node (e.g. a wireless device having a higher RSRP/RSRQ from a cell of the second network node than a handover threshold RSRP/RSRQ employed in case of a stable backhaul link connection (e.g. higher backhaul link RSRP/RSRQ than the updated value and/or X dB)).

In an example, a wireless device may receive, from a first network node (e.g. and/or from the second network node), at least one radio resource control (RRC) message comprising configuration parameters of a first cell of a second network node. The wireless device may transmit, to the second network node, packets based on (explain in spec) the configuration parameters. The wireless device may determine a connection failure from the first network node (e.g. and/or from the second network node) based on a backhaul link failure (e.g. backhaul link problem, backhaul link blockage). The wireless device may select, in response to the connection failure, a second cell of a third network node for a radio resource control connection (e.g. establishment and/or reestablishment). The wireless device may transmit, to the third network node, a radio link failure report comprising a cause value of the connection failure. The cause value may indicate that the backhaul link failure caused the connection failure.

In an example, the wireless device may receive, from the second network node, a backhaul link failure information indicating a failure (e.g. problem, blockage) of a first radio link established between the first network node and the second network node. In an example, the wireless device may determine the connection failure based on the backhaul link failure information. In an example, the wireless device may receive the backhaul link failure information via at least one of a medium access control control element (MAC CE), a physical layer command comprising downlink control information, an adaptive layer indication, and/or a radio resource control message (e.g. RRC connection release message).

In an example, the backhaul link failure information may comprise at least one of: a first node identifier of the first network node; a second node identifier of the second network node; a failure (e.g. blockage, problem) type (e.g. comprising at least one of: a temporary blockage; a failure of at least one of multiple backhaul links of the second network node; and/or a failure of all backhaul links of the second network node); a timer value for determining an integrated access and backhaul node failure; an indication parameter indicating a state transition into a dormant state of one or more cells of the second network node; an indication parameter indicating release of one or more cells of the second network node; a cause value of the failure (e.g. RLF cause) of the first radio link; a bearer identifier of a bearer affected by the failure of the first radio link; and/or a cell identifier of a cell (e.g. employed by the second network node) of the first network node (e.g. the cell causing the failure of the first radio link).

In an example, the wireless device may release, in response to receiving the backhaul link failure information, a bearer established via the second network node. In an example, the wireless device may stop, in response to receiving the backhaul link failure information, transmission of a scheduling request to the second network node. In an example, the first radio link may comprise one or more radio links connected via one or more network nodes. The failure of the first radio link may indicate at least one failure of the one or more radio links.

In an example, the wireless device may transmit, via the second cell, one or more random access preambles. The wireless device may receive, from the third network node, a random access response for the one or more random access preamble. The wireless device may transmit, based on the random access response, a radio resource control connection (e.g. reestablishment and/or establishment) request message.

In an example, the connection failure may comprise at least one of a radio link failure and/or a handover failure. The first cell may be a primary cell of the wireless device. The first network node may comprise the third network node. The second network node may comprise the third network node. In an example, the first cell may be the second cell. In an example, the radio link failure report may comprise at least one of: an identifier of the first network node; an identifier of the second network node; a base station identifier of the second network node; an integrated access and backhaul identifier of the second network node; a transmit and reception point identifier of the second network node; a cell identifier of the first cell; a beam identifier of the first cell; a beam group identifier of one or more beams of the first cell; an F1 wireless device identifier of the wireless device; an information element indicating that the backhaul link failure caused the connection failure; a failure (e.g. blockage, problem) type (e.g. comprising at least one of: a temporary blockage; a failure of at least one of multiple backhaul links of the second network node; and/or a failure of all backhaul links of the second network node); a timer value for determining an integrated access and backhaul node failure; a cause value of the failure (e.g. RLF cause) of the first radio link; and/or a cell identifier of a cell (e.g. employed by the second network node) of the first network node (e.g. the cell causing the failure of the first radio link).

In an example, the first network node may comprise at least one of: a base station; a base station central unit; and/or an integrated access and backhaul donor. In an example, the second network node may comprise at least one of: a base station; a base station distributed unit; and/or an integrated access and backhaul node.

In an example, the first network node may receive, from the third network node, one or more elements of the radio link failure report. The first network node may configure radio resource configuration parameters based on the one or more elements of the radio link failure report. In an example, the radio resource configuration parameters may comprise beam configuration parameters for the second network node. In an example, the radio resource configuration parameters may comprise handover triggering parameters for an integrated access and backhaul node. The handover triggering parameters may comprise at least one of a radio signal received quality value (e.g. threshold quality value) and/or a radio signal received power value (e.g. threshold power value). In an example, the first network node may transmit, to the second network node, the one or more elements of the radio link failure report.

In an example, a wireless device may receive, from a first network node, at least one radio resource control message comprising configuration parameters of a first cell of a second network node. The wireless device may transmit, to the second network node, packets based on the configuration parameters. The wireless device may receive, from the second network node, a backhaul link failure information indicating a failure of a first radio link established between the first network node and the second network node. The wireless device may determine a connection failure from the first network node based on the backhaul link failure information. The wireless device may select, in response to the connection failure, a second cell of the first network node for a radio resource control connection. The wireless device may transmit, to the first network node, a radio link failure report comprising a cause value of the connection failure, wherein the cause value indicates that the backhaul link failure caused the connection failure.

In an example, a wireless device may receive, from a first network node, at least one radio resource control message comprising configuration parameters of a first cell of a second network node. The wireless device may transmit, to the second network node, packets based on the configuration parameters. The wireless device may receive, from the second network node, a backhaul link failure information indicating a failure of a first radio link established between the first network node and the second network node. The wireless device may determine a connection failure from the first network node based on the backhaul link failure information. The wireless device may select, in response to the connection failure, a second cell of the second network node for a radio resource control connection. The wireless device may transmit, to the second network node, a radio link failure report comprising a cause value of the connection failure, wherein the cause value indicates that the backhaul link failure caused the connection failure.

In an example, a wireless device may receive, from a first network node via a second network node, at least one radio resource control message comprising configuration parameters of a first cell of the second network node. The wireless device may send, to the second network node, packets via the first cell. The wireless device may determine a failure of a connection to the first network node based on a backhaul link failure between the first network node and the second network node. The wireless device may select, based on the determining the failure of the connection, a second cell of a third network node for a radio resource control connection. The wireless device may transmit, to the third network node, a radio link failure report indicating the backhaul link failure.

In an example, the wireless device may receive, from the second network node, a backhaul link failure information indicating a failure of a first radio link established between the first network node and the second network node. The wireless device may receive the backhaul link failure information via at least one of: a medium access control control element, a physical layer command comprising downlink control information, an adaptive layer indication, a radio resource control message, and/or the like. In an example, the wireless device may determine the failure of the connection based on the backhaul link failure information. The backhaul link failure information may comprise at least one of: a first node identifier of the first network node; a second node identifier of the second network node; a failure type (e.g., comprising at least one of: a temporary blockage, a failure of at least one of multiple backhaul links of the second network node, a failure of all backhaul links of the second network node, etc.); a timer value for determining an integrated access and backhaul node failure; an indication parameter indicating a state transition into a dormant state of one or more cells of the second network node; an indication parameter indicating release of one or more cells of the second network node; a cause value of the failure of the first radio link; a bearer identifier of a bearer affected by the failure of the first radio link; a cell identifier of a cell of the first network node, the cell causing the failure of the first radio link; and/or the like.

In an example, the wireless device may release, in response to receiving the backhaul link failure information, a bearer established via the second network node. The wireless device may stop, in response to receiving the backhaul link failure information, transmission of a scheduling request to the second network node. The first radio link may comprise one or more radio links connected via one or more network nodes. The failure of the first radio link may indicate at least one failure of the one or more radio links.

In an example, the wireless device may transmit, via the second cell, one or more random access preambles. The wireless device may receive, from the third network node, a random access response for the one or more random access preamble. The wireless device may transmit, to the third network node and based on the random access response, a radio resource control connection request message. The failure of the connection may comprise at least one of: a radio link failure, a handover failure, and/or the like. The first cell may be a primary cell of the wireless device. The first cell may be the second cell. The first network node may be the third network node. The second network node may be the third network node. The radio link failure report may comprise at least one of: an identifier of the first network node, an identifier of the second network node, a base station identifier of the second network node, an integrated access and backhaul identifier of the second network node, a transmit and reception point identifier of the second network node, a cell identifier of the first cell, a beam identifier of the first cell, a beam group identifier of one or more beams of the first cell, an F1 wireless device identifier of the wireless device, an information element indicating that the backhaul link failure caused the failure of the connection, a failure type (e.g., comprising at least one of: a temporary blockage, a failure of at least one of multiple backhaul links of the second network node, a failure of all backhaul links of the second network node, etc.), a timer value for determining an integrated access and backhaul node failure, a cause value of the failure of the first radio link, a cell identifier of a cell of the first network node (e.g., the cell may cause the failure of the first radio link), and/or the like.

In an example, the first network node may comprise at least one of: a base station, a base station central unit, an integrated access and backhaul donor, and/or the like. The second network node may comprise at least one of: a base station, a base station distributed unit, an integrated access and backhaul node, and/or the like.

In an example, the first network node may receive, from the third network node, one or more elements of the radio link failure report. The first network node may configure radio resource configuration parameters based on the one or more elements. The radio resource configuration parameters may comprise beam configuration parameters for the second network node. The radio resource configuration parameters may comprise handover triggering parameters for an integrated access and backhaul node. The handover triggering parameters may comprise at least one of: a radio signal received quality value, a radio signal received power value, and/or the like. The first network node may transmit, to the second network node, the one or more elements of the radio link failure report.

In an example, as shown in FIG. 45, a wireless device may communicate with a first network node via a second network node, 4510. The wireless device may send, to a third network node, a radio link failure report indicating a backhaul link failure between the first network node and the second network node, 4520.

In an example, as shown in FIG. 46, a third network node may receive, from a wireless device, a radio link failure report indicating a backhaul link failure between a first network node and a second network node, 4610. A failure of a connection between the wireless device and the first network node via the second network node may be based on the backhaul link failure, 4620. The third network node may send, to the first access node, one or more elements of the radio link failure report.

In an example, a wireless device may send a radio link failure report indicating that a connection failure between the wireless device and a first network node, via a second network node, is based on a backhaul link failure between the first network node and the second network node.

In an example, a wireless device may send a radio link failure report indicating a backhaul link failure between a first network node and a second network node. A connection failure between the wireless device and the first network node via the second network node may be based on the backhaul link failure.

In an example, a wireless device may send a radio link failure report indicating a backhaul link failure between a first network node and a second network node. The wireless device may communicate with the first network node via the second network node prior to the backhaul link failure.

In an example, a wireless device may send, to a third network node, a radio link failure report indicating a backhaul link failure between a first network node and a second network node. The wireless device may communicate with the first network node via the second network node prior to the backhaul link failure.

In an example, a wireless device may determine a failure of a connection between the wireless device and a first network node via a second network node, based on a backhaul link failure between the first network node and the second network node. The wireless device may send, to a third network node, a radio link failure report indicating the backhaul link failure.

In an example, a wireless device may receive, from a first network node, at least one radio resource control message comprising configuration parameters of a first cell of a second network node. The wireless device may transmit, to the second network node, packets based on the configuration parameters. The wireless device may receive, from the second network node, a backhaul link failure information indicating a failure of a first radio link established between the first network node and the second network node. The wireless device may determine a connection failure from the first network node based on the backhaul link failure information. The wireless device may select, based on the connection failure, a second cell of a third network node for a radio resource control connection. The wireless device may transmit, to the third network node, a radio link failure report comprising a cause value of the connection failure. The cause value may indicate that the backhaul link failure caused the connection failure.

Embodiments may be configured to operate as needed. The disclosed mechanism may be performed when certain criteria are met, for example, in a wireless device, a base station, a radio environment, a network, a combination of the above, and/or the like. Example criteria may be based, at least in part, on for example, wireless device or network node configurations, traffic load, initial system set up, packet sizes, traffic characteristics, a combination of the above, and/or the like. When the one or more criteria are met, various example embodiments may be applied. Therefore, it may be possible to implement example embodiments that selectively implement disclosed protocols.

A base station may communicate with a mix of wireless devices. Wireless devices and/or base stations may support multiple technologies, and/or multiple releases of the same technology. Wireless devices may have some specific capability(ies) depending on wireless device category and/or capability(ies). A base station may comprise multiple sectors. When this disclosure refers to a base station communicating with a plurality of wireless devices, this disclosure may refer to a subset of the total wireless devices in a coverage area. This disclosure may refer to, for example, a plurality of wireless devices of a given LTE or 5G release with a given capability and in a given sector of the base station. The plurality of wireless devices in this disclosure may refer to a selected plurality of wireless devices, and/or a subset of total wireless devices in a coverage area which perform according to disclosed methods, and/or the like. There may be a plurality of base stations or a plurality of wireless devices in a coverage area that may not comply with the disclosed methods, for example, because those wireless devices or base stations perform based on older releases of LTE or 5G technology.

In this disclosure, “a” and “an” and similar phrases are to be interpreted as “at least one” and “one or more.” Similarly, any term that ends with the suffix “(s)” is to be interpreted as “at least one” and “one or more.” In this disclosure, the term “may” is to be interpreted as “may, for example.” In other words, the term “may” is indicative that the phrase following the term “may” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments.

If A and B are sets and every element of A is also an element of B, A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B={cell1, cell2} are: {cell1}, {cell2}, and {cell1, cell2}. The phrase “based on” (or equally “based at least on”) is indicative that the phrase following the term “based on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “in response to” (or equally “in response at least to”) is indicative that the phrase following the phrase “in response to” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “depending on” (or equally “depending at least to”) is indicative that the phrase following the phrase “depending on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “employing/using” (or equally “employing/using at least”) is indicative that the phrase following the phrase “employing/using” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments.

The term configured may relate to the capacity of a device whether the device is in an operational or non-operational state. Configured may also refer to specific settings in a device that effect the operational characteristics of the device whether the device is in an operational or non-operational state. In other words, the hardware, software, firmware, registers, memory values, and/or the like may be “configured” within a device, whether the device is in an operational or nonoperational state, to provide the device with specific characteristics. Terms such as “a control message to cause in a device” may mean that a control message has parameters that may be used to configure specific characteristics or may be used to implement certain actions in the device, whether the device is in an operational or non-operational state

In this disclosure, various embodiments are disclosed. Limitations, features, and/or elements from the disclosed example embodiments may be combined to create further embodiments within the scope of the disclosure.

In this disclosure, parameters (or equally called, fields, or Information elements: IEs) may comprise one or more information objects, and an information object may comprise one or more other objects. For example, if parameter (IE) N comprises parameter (IE) M, and parameter (IE) M comprises parameter (IE) K, and parameter (IE) K comprises parameter (information element) J. Then, for example, N comprises K, and N comprises J. In an example embodiment, when one or more (or at least one) message(s) comprise a plurality of parameters, it implies that a parameter in the plurality of parameters is in at least one of the one or more messages, but does not have to be in each of the one or more messages. In an example embodiment, when one or more (or at least one) message(s) indicate a value, event and/or condition, it implies that the value, event and/or condition is indicated by at least one of the one or more messages, but does not have to be indicated by each of the one or more messages.

Furthermore, many features presented above are described as being optional through the use of “may” or the use of parentheses. For the sake of brevity and legibility, the present disclosure does not explicitly recite each and every permutation that may be obtained by choosing from the set of optional features. However, the present disclosure is to be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features may be embodied in seven different ways, namely with just one of the three possible features, with any two of the three possible features or with all three of the three possible features.

Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined here as an element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software in combination with hardware, firmware, wetware (i.e. hardware with a biological element) or a combination thereof, all of which may be behaviorally equivalent. For example, modules may be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab or the like) or a modeling/simulation program such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript. Additionally, it may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and/or quantum hardware. Examples of programmable hardware comprise: computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers and microprocessors are programmed using languages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. The above mentioned technologies are often used in combination to achieve the result of a functional module.

The disclosure of this patent document incorporates material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, for the limited purposes required by law, but otherwise reserves all copyright rights whatsoever.

While various embodiments have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art(s) that various changes in form and detail can be made therein without departing from the scope. In fact, after reading the above description, it will be apparent to one skilled in the relevant art(s) how to implement alternative embodiments. Thus, the present embodiments should not be limited by any of the above described exemplary embodiments.

In addition, it should be understood that any figures which highlight the functionality and advantages, are presented for example purposes only. The disclosed architecture is sufficiently flexible and configurable, such that it may be utilized in ways other than that shown. For example, the actions listed in any flowchart may be re-ordered or only optionally used in some embodiments.

Further, the purpose of the Abstract of the Disclosure is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The Abstract of the Disclosure is not intended to be limiting as to the scope in any way.

Finally, it is the applicant's intent that only claims that include the express language “means for” or “step for” be interpreted under 35 U.S.C. 112. Claims that do not expressly include the phrase “means for” or “step for” are not to be interpreted under 35 U.S.C. 112. 

1. A method comprising: receiving, by a wireless device from a first network node via a second network node, at least one radio resource control message comprising configuration parameters of a first cell of the second network node; transmitting, by the wireless device to the second network node, packets via the first cell; determining, by the wireless device, a failure of a connection to the first network node based on a backhaul link failure between the first network node and the second network node; selecting, by the wireless device and based on the determined failure of the connection, a second cell of a third network node for a radio resource control connection; and transmitting, by the wireless device to the third network node, a radio link failure report indicating the backhaul link failure.
 2. The method of claim 1, wherein determining the failure of the connection to the first network node comprises: receiving, by the wireless device from the second network node, backhaul link failure information indicating a failure of a first radio link established between the first network node and the second network node.
 3. The method of claim 2, wherein the wireless device receives the backhaul link failure information via at least one of: a medium access control control element; a physical layer command comprising downlink control information; an adaptive layer indication; or a radio resource control message.
 4. The method of claim 2, wherein the backhaul link failure information comprises a failure type comprising at least one of: a temporary blockage; a failure of at least one of multiple backhaul links of the second network node; or a failure of all backhaul links of the second network node.
 5. The method of claim 2, wherein the backhaul link failure information comprises a cell identifier of a cell, of the first network node, causing the failure of the first radio link.
 6. The method of claim 2, further comprising releasing, by the wireless device and in response to receiving the backhaul link failure information, a bearer established via the second network node.
 7. The method of claim 2, further comprising stopping, by the wireless device and in response to receiving the backhaul link failure information, transmission of a scheduling request to the second network node.
 8. The method of claim 2, wherein the first radio link comprises one or more radio links connected via one or more network nodes, and the failure of the first radio link indicates at least one failure of the one or more radio links.
 9. The method of claim 1, further comprising: transmitting, by the wireless device via the second cell, one or more random access preambles; receiving, by the wireless device from the third network node, a random access response for the one or more random access preamble; and transmitting, by the wireless device to the third network node and based on the random access response, a radio resource control connection request message.
 10. The method of claim 1, wherein the radio link failure report comprises at least one of: an information element indicating that the backhaul link failure caused the failure of the connection; or a cell identifier of a cell, of the first network node, causing the failure of a first radio link established between the first network node and the second network node.
 11. The method of claim 1, wherein the radio link failure report comprises a cell identifier of the first cell.
 12. A wireless device comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the wireless device to: receive, from a first network node via a second network node, at least one radio resource control message comprising configuration parameters of a first cell of the second network node; transmit, to the second network node, packets via the first cell; determine a failure of a connection to the first network node based on a backhaul link failure between the first network node and the second network node; select, based on the determined failure of the connection, a second cell of a third network node for a radio resource control connection; and transmit, to the third network node, a radio link failure report indicating the backhaul link failure.
 13. The wireless device of claim 12, wherein to determine the failure of the connection to the first network node, the instructions, when executed by the one or more processors, further cause the wireless device to receive, from the second network node, a backhaul link failure information indicating a failure of a first radio link established between the first network node and the second network node.
 14. The wireless device of claim 13, wherein the instructions, when executed by the one or more processors, further cause the wireless device to receive the backhaul link failure information via at least one of: a medium access control control element; a physical layer command comprising downlink control information; an adaptive layer indication; or a radio resource control message.
 15. The wireless device of claim 13, wherein the backhaul link failure information comprises a failure type comprising at least one of: a temporary blockage; a failure of at least one of multiple backhaul links of the second network node; or a failure of all backhaul links of the second network node.
 16. The wireless device of claim 13, wherein the backhaul link failure information comprises a cell identifier of a cell, of the first network node, causing the failure of the first radio link.
 17. The wireless device of claim 13, wherein the first radio link comprises one or more radio links connected via one or more network nodes, and the failure of the first radio link indicates at least one failure of the one or more radio links.
 18. The wireless device of claim 12, wherein the radio link failure report comprises at least one of: an information element indicating that the backhaul link failure caused the failure of the connection; or a cell identifier of a cell, of the first network node, causing the failure of the first radio link.
 19. The wireless device of claim 12, wherein the radio link failure report comprises a cell identifier of the first cell.
 20. A non-transitory computer-readable storage medium comprising instructions that, when executed by one or more processors, cause the one or more processors to perform instructions comprising: receiving, from a first network node via a second network node, at least one radio resource control message comprising configuration parameters of a first cell of the second network node; transmitting, to the second network node, packets via the first cell; determining a failure of a connection to the first network node based on a backhaul link failure between the first network node and the second network node; selecting, based on the determined failure of the connection, a second cell of a third network node for a radio resource control connection; and transmitting, to the third network node, a radio link failure report indicating the backhaul link failure. 